When I started using Windows 2000 Server in early 1999, one of the first things I noticed about the OS was that I couldn't find any of the tools I wanted. More than a year later, navigating the OS is straightforward, but my first attempts at using Win2K Server were frustrating: I felt as if I didn't know how to do anything.
Because Win2K Professional and Windows 9x are more alike than Win2K Server and Windows NT 4.0, Win9x users who are getting acquainted with Win2K Pro won't experience quite the same frustration. However, Win9x users will still find many differences between the Win9x user interface (UI) and the Win2K Pro UI. Although some features remain the same, some contain new options not available in Win9x, and some are completely different or entirely new to Win2K Pro. A plethora of minor differences (e.g., changes in wording) exist, but I want to concentrate on the Win2K Pro changes most likely to confound power users who have been using Win9x and need to translate their expertise to the new OS.
Finding My Tools
Let's open Win2K Pro and examine the potential new locations for your essential tools. Start at Control Panel, which you'll find under Start, Settings, just as in Win9x. (You can also access Control Panel from the My Computer window or from Windows Explorer, which you'll find in Accessories instead of in Programs.) Control Panel contains applets for many system settings—similar but not identical to the applets in the Win9x Control Panel—and contains links to the Network and Dial-up Connections, Printers, and Administrative Tools folders. Network and Dial-up Connections contains tools that let you edit network settings; Printers contains printer-management tools; and Administrative Tools contains a suite of advanced system management tools that are generally new to Win9x users. In Win2K Pro, the System Tools folder (which you find under Programs, Accessories, System Tools) contains disk-management and data-management tools (e.g., backup, defragmentation), just as Win9x's System Tools folder does.
The new Administrative Tools folder contains shortcuts to advanced configuration and management tools. The tools you're likely to use are the following:
- Computer Management: Serves as the interface for many different computer-management tools, such as disk management, performance logging, and local user account administration. Computer Management is a catchall location for several of Win2K Pro's systems administration tools.
- Event Viewer: Lists system events for applications, the OS, and security auditing. Logged events are messages that inform you whether something happened as expected (e.g., a successful virus check that finds no viruses), warnings about conditions in which something might go wrong (e.g., nearing a disk quota), or messages informing you that something has gone wrong (e.g., an inability to find the master browser).
- Local Security Policy: Configures local security policies for auditing, passwords, and user account lockouts.
- Performance: Gathers performance data for user-specified objects on the computer (or on other computers).
- Services: Edits service settings on the computer. Services are "helper applications" that run in the context of the System account and provide support for hardware and software. For example, the print spooler, which collects print jobs for the print device, is a service. Services are different from applications primarily in terms of the security settings associated with them. An application runs according to the security settings of the person who started it. (If a user runs Microsoft Word, Word can't do anything that the user doesn't have permission to do.) Typically, the System account, which can do anything, starts services.
- Telnet Server Administration: Edits the settings for the Telnet server (which lets people telnet into your computer).
The Administrative Tools folder contains fewer tools than you might think. Although you see many tools, some are redundant. For example, you can also access Services from Component Services. Computer Management, which Figure 1 shows, contains Services, Event Viewer, and all the disk-management tools in the System Tools folder.
Grouping the Tools
The simplest way to discuss Win2K Pro's tools is to group them into six functions—computer management, disk maintenance, UI settings, user account management, network settings, and troubleshooting. Although I don't have space to describe all these options in great detail, after reading this article you should know how to find and use these tools within the Win2K UI.
How do I back up my computer's configuration and my data?
Like NT, Win2K has mechanisms for backing up configuration data, copying current Registry settings to a backup directory, and creating an Emergency Repair Disk (ERD). Remember that an ERD isn't the same as the Win9x Startup Disk—an ERD isn't bootable and is useful only for repairing data. (For more information about the Win2K ERD, how to use it, and how it compares with NT's ERD, see "Windows 2000 Server Recovery Tools," Winter 1999.)
To create an ERD, go to Programs, Accessories, System Tools, Backup and click Emergency Repair Disk. To update the Repair information on your computer, make sure that you select the Update repair information check box. If you don't select this check box, when you repair your installation, you'll restore the system to the configuration you specified when you installed the OS. Always update the Repair information before you make any major changes to your OS.
Creating an ERD and updating the Repair information backs up only the Registry. You can also back up the COM+ database and class associations—as well as system boot files—with the Backup tool's data component. Click Backup Wizard, and while following the wizard, choose to back up System State data (or select the System State check box on the Backup tab). You can also back up System State data by choosing to back up all data on your computer. Although the default backup location is a 3.5" disk (if you don't have a tape drive installed), the System State data won't fit on one disk. Instead, you'll need to back up to your hard disk or to another network location. (For more information about backing up System State data, see Sean Daily, "Daily Answers," October 2000.)
To back up your data, run the Backup Wizard and choose the option to back up all data or the option to back up selected files, disks, or network data. Alternatively, on the Backup tab, you can select the specific files and folders you want to back up. Again, the default backup destination is a 3.5" disk, but Win2K Backup supports backups to most media.
How do I find files?
Win2K's Search option, which you see when you access the Start menu, gives you the same functionality that Win9x's Find option offers. However, if you often search the same areas of your hard disk, you have a quicker option. Win2K offers an indexing service that you can use on your computer's local disks. To find a file on your computer, go to Control Panel, Administrative Tools, Computer Management. In the Services and Applications folder, click the Indexing Service icon. To add indexable areas, right-click in the right pane and choose New from the context menu. In the Add Catalog dialog box, click Browse or type the path to the volume you want to index. The path must exist on your local computer.
The Indexing service not only lets you perform faster searches (because it catalogs your hard disk) but also gives you far more control over how you perform searches on your hard disk than you have with the standard Search tool. For example, you can use vector-search queries that weight certain word combinations to have a higher ranking. If you use Indexing Service and are interested in powerful searches, be sure to check the Help files for information about how to use the query language.
How do I install or remove software?
Win9x users will be familiar with the Control Panel Add/Remove Programs applet but might be flummoxed by its appearance in Win2K Pro. To add a new application, open the applet to show the screen that Figure 2, page 70, shows. Click Add New Programs, and choose the appropriate source: CD or Floppy, or Windows Update. If you choose CD or Floppy, you'll need to provide the path to the installation files, then walk through the installation wizard as you do in Win9x. If your network is using IntelliMirror to distribute applications, you don't need to do anything to install the application. When you click the application's icon, the application is automatically installed.
To remove an existing application, click Change or Remove Programs to display a list of all currently installed applications. Click the application's entry. What you see next depends on whether the application used Windows Installer for its setup program. If it did, you'll see both a Change button and a Remove button. Clicking Change will rerun Setup and let you modify any settings for the application. Remove, which is available whether or not an application used the Windows Installer, does exactly what you'd expect it to do.
How do I install or remove Windows components?
Win2K has many optional components that you can add while you are installing the OS or afterward. (Indexing Service is one optional component; others include network-management tools and a Web server.) To add these components after installation, click the Add/Remove Windows Components icon on the Add/Remove Programs screen, and wait while Win2K assembles a list of available services.
For information about a particular service, select it to display a brief description. When you select a service that has subcomponents (e.g., Networking Services), the Details button appears. Click Details to choose subcomponents. When you click Next, Win2K installs the services and subcomponents that you selected (or uninstalls the services that you selected for uninstallation). You might need to reboot after you install services.
How do I install new hardware or edit settings for existing hardware?
The process you use to install new hardware is similar to the process you use in Win9x, except that Win9x's Control Panel Add Hardware applet is called Add/Remove Hardware in Win2K Pro. To install a new device or troubleshoot a device that is already in place, simply follow the wizard's instructions.
If you want to view the settings for an already-installed piece of hardware, or if you want to install a new driver, you'll need Device Manager, which Figure 3 shows. You access Device Manager from Control Panel, Administrative Tools, Computer Management, System Tools or from the Control Panel System applet's Hardware tab. Device Manager has the same functionality as Win9x's Device Manager, except that in Win2K Pro, you access the Properties and Remove buttons by right-clicking a device. Also, Win9x's Refresh option is called Scan for hardware changes in Win2K Pro.
How do I install or connect to a new printer?
Installing a new printer in Win2K is very much like installing a printer in Win9x. Simply run the Add Printer wizard (which you access from the Printers folder), and indicate whether you're installing a new printer or connecting to a printer that is already installed somewhere on the network. If you're installing a new printer and sharing it, the wizard asks for location and description information, but only Win2K clients can read the information in the Location box. Therefore, in a mixed environment, be sure to put important descriptive information in the Comment box.
If you're connecting to a printer on your Win2K-based network, you might find a printer in Active Directory (AD). You can browse by the name of the server to which the printer is connected, by keywords associated with the printer, or by other criteria. After you find the printer, the connection process is much like connecting from Win9x.
How do I edit the power-management settings?
Win9x has offered impressive power-management tools for a while (unlike NT). Win2K uses similar tools. You can reach Win2K's power-management settings from the Control Panel Power Options applet. The Power Schemes tab might look familiar to Win9x users. The only real difference is hibernation support for laptop users. Hibernation is a power-saving measure wherein Win2K writes all the current desktop information to disk and enters a low-power state. Win2K restores the information when you press the power button to bring the laptop back to life.
How do I schedule tasks?
Win2K supports two scheduling tools. From the command prompt, you can use the At command to schedule tasks (e.g., backups). You can also find a task scheduler under Programs, Accessories, System Tools. When you start the scheduler, you can follow the Add Scheduled Task wizard to pick an application to run once or at a certain time according to an interval you set. However, the Schedule Jobs tool only runs an application—you can't feed it arguments. Generally, the At command is better for scheduling actual tasks, except for backups, which are well integrated with the scheduler. For more information about the At scheduler, see Mark Minasi, Inside Out, "Where It's AT," March 1998, and This Old Resource Kit, "A Better AT," April 1998.
How do I defragment my hard disk?
To defragment your hard disk under Win2K, follow the same procedures you use in Win9x: Open Programs, Accessories, System Tools, Disk Defragmenter. You'll also find the defragging tool in Computer Management's Storage section, which Figure 4 shows, and on the Tools tab of a disk's Properties sheet.
How do I format a disk?
Win2K offers a few ways to format a disk. First, you can go to My Computer or Windows Explorer, just as you would in Win9x: Right-click the disk you want to format, and choose Format from the context menu. Second, you can format a disk while you're creating a new volume on your computer. Third, you can use the Format command-line utility, which also comes with Win9x and has the same syntax:
The volume name can be a drive letter, mount point, or volume name, and the disk format can be FAT, FAT32, or NTFS. If you don't specify a disk format, the default option for floppy disks is FAT and for fixed disks is NTFS. (Because of a floppy disk's size, its only option is FAT.)
How do I convert a volume to NTFS?
NTFS is a more secure file system than FAT or FAT32 and can reduce seek times on large disks. If you format a volume to FAT or FAT32 and about one-third of the volume is unused, you can later convert it to NTFS without destroying the disk's data. From the command prompt, type
where volume name is the mount point, drive letter, or volume name. The only catch is that the process is irreversible. Although Win9x offers a Drive Converter, Win2K has no Convert utility to go to FAT32—and only NT 4.0 Service Pack 4 (SP4) and later can read Win2K's version of NTFS on the local computer. Other locally installed OSs (e.g., Win98) won't be able to read the volume at all.
How do I create a new volume?
Power users know that Win9x is missing some serious disk-management utilities. Win2K offers such tools. Using the new Disk Management utility from Computer Management's Storage section, you can create new volumes from Win2K.
To create a new volume from unpartitioned space, right-click the gray disk labeled Disk 0 (or Disk 1, and so on), then choose Create Partition from the context menu. If the space is unpartitioned, you'll need to first create a primary or extended partition. When you create a primary partition, you create a volume that you can assign a drive letter to and that will hold data. When you create an extended partition, you create an area of free space that you can subdivide into logical drives by right-clicking the extended partition and choosing that option.
Win2K supports single-disk volumes and multidisk volumes. If your computer has more than one physical disk, you can make the disks dynamic and thus create volumes that extend across the disks. Win2K Pro doesn't support fault-tolerant volumes, but using dynamic disks to create volumes lets you combine noncontiguous disk spaces into one volume—even extending across an existing volume. Therefore, dynamic disks are more space-efficient than primary partitions or logical disks.
To upgrade a disk to dynamic, right-click its gray label and choose the Upgrade to Dynamic Disk option from the context menu. Before you upgrade, be very sure that you want a dynamic disk. Dynamic disks aren't visible to any locally installed OS other than Win2K—important on dual-boot systems—and you can't revert a disk to basic without first deleting every volume on the disk. You can make only fixed disks dynamic (i.e., no removable or CD-Rewritable—CD-RW—disks), and laptops don't support dynamic disks at all. For more information about partition types and fault-tolerant volumes, see Sean Daily, "Discover Dynamic Disks," June 2000.
How do I check a disk's integrity?
Like Win9x, Win2K lets you use a graphical or command-line tool to check disk integrity, but Win2K's options and UI are different. Win2K's graphical Chkdsk utility—which you access from the Tools tab of a disk's Properties sheet by clicking Check Now—lets you run a read-only scan or attempt to fix file-system errors (i.e., the equivalent of the command-line /f option) and recover bad sectors. Chkdsk doesn't have a Verbose option, so following a read-only scan, all you get is a message box informing you that the scan has completed.
If you want more complete information about your disk's condition, use the command prompt. If you type
you'll find that the available switches and the effects of switches depend on which file system you're using. For example, to check drive C (formatted with NTFS), fix file-system errors, and get a complete report of any cleanup errors, type
chkdsk C: /v /f
How do I disable Personalized Menus?
By default, Win2K enables Personalized Menus. Therefore, only the menu items that you use most often will be visible. Options that you use less often will be visible if you click an arrow on the menu. Although Personalized Menus keep your desktop a little neater, they cause trouble when you need to find a specific option that you don't use often.
To disable Personalized Menus, go to the Start menu and select Settings, Taskbar & Start Menu. On the General tab, clear the Use Personalized Menus check box.
How do I change the contents of the Taskbar and Start menu?
Win2K's process for adding shortcuts to the Taskbar and Start menu is similar to that of Win9x. The simplest way to add a program to the Start menu is to drag the icon to the Start button. However, you can also go to the Start menu and choose Settings, Taskbar & Start Menu. Then, go to the Advanced tab and click Add. A wizard helps you add the shortcut.
If you need to change the path of a shortcut already on the Start menu, you don't need to add it again. Simply click Advanced on the same tab, browse the menu for the application's icon, then click Properties to edit its path.
How do I change the desktop's appearance?
Changing Win2K's desktop appearance isn't much different from changing Win9x's. The Control Panel Display applet controls such cosmetic items as appearance and wallpaper. Win9x users will see minor changes in wording, and the Web and Effects tabs are reversed. Also, Win2K offers some cool new wallpaper, which now resides in \%systemroot%web\wallpaper, not in the \windows directory. However, Win2K doesn't offer desktop themes.
Win2K lets you hide desktop items. To do so, right-click on the desktop, select Active Desktop, and clear the Show Desktop Icons check box. You'll see another option to Lock Desktop Items. Enabling this option doesn't prevent you from adding or removing items on your desktop. Rather, it prevents you from removing or resizing Active Desktop items (e.g., a Web-based news ticker). The option doesn't affect other shortcuts or applications that aren't dependent on the Active Desktop.
User Account Management
How do I add or delete locally stored user accounts?
You might have locally stored user accounts. By default, Win2K creates an Administrator account and a disabled Guest account. You can manage these local user accounts from Local Users and Groups (part of the Computer Management tool in the Administrative Tools folder) or from the Control Panel Users and Passwords applet. Local Users and Groups gives you more discretionary control over user accounts.
To permit a user who already has a domain account to use the local computer, open the Users and Passwords applet and go to the Users tab. Click Add to start a wizard in which you specify an existing user account to log on to the machine. To add a local account, you'll need the Local Users and Groups tool in Computer Management. (You can also access Local Users and Groups by clicking Advanced on the Advanced tab of the Users and Passwords applet.) Open the Users folder so that the accounts are visible in the right pane, then right-click within the pane and choose New User from the context menu. Enter the user's name and password. After you add the new account to the list, right-click the account and choose Properties to add the new account to a group. By default, all new accounts are members of the local Users group.
Adding or removing a user account from the Users and Passwords applet will automatically update Local Users and Groups, and vice versa. The Users and Passwords applet and Local Users and Groups are accessing the same information database; they're simply presenting the information differently.
How do I disable locally stored user accounts?
Disabling a user account prevents anyone from using it to log on. To disable an account, find its entry in Local Users and Groups, right-click the account name, and open its Properties sheet. On the General tab, select the Account is Disabled check box. In the list of user accounts, the disabled account will have a red icon with a white X on it.
How do I change the password on a local account? To change the password on a nonadministrative account, find the account's entry on the Users tab in the Users and Passwords applet. Click Set Password, and type in the new password. Administrators need to press Ctrl+Alt+Del, then choose Change Password. Alternatively, you can open the Local Users and Groups tool in Computer Management, right-click an account, and choose Set Password from the context menu.
How do I set a profile or home directory path for locally stored accounts?
To set the profile or home directory path for a local account, open the account's Properties sheet and go to the Profile tab. Type in the path to the profile and home directory.
How do I change my computer's name and domain or workgroup affiliation?
In Win9x, network settings are all available from the Control Panel Network applet. In Win2K, however, network settings are available in two locations: the System applet and the Network and Dial-up Connections folder. All settings related to your computer's identity on the network are accessible from the System applet.
To change your computer's name or join a domain or workgroup, you can walk through the Network Identification wizard. However, power users will probably find the following method faster: Open the System applet, go to the Network Identification tab, and click Properties to open the Identification Changes dialog box that Figure 5 shows.
Anyone can join a workgroup. (In fact, if you're not careful about the spelling of the workgroup you choose to join, you'll inadvertently create a new one.) However, to join a domain, you'll need the name and password of someone who has administrative privileges on the domain controller and can therefore add your computer's name to the security database—part of the process of joining a domain.
How do I add protocols, network drivers, and services?
To add a new protocol, open the Network and Dial-up Connections folder and right-click Local Area Connections. Select Properties to access the dialog box that Figure 6 shows. To add a service, client, or network protocol, click Install. As you do in Win9x, choose the type of software you want to install.
In Win2K, you don't install network cards or update drivers from the same place that you install protocols from. Instead, click Configure to edit the current settings of an existing network card or to update its driver.
How do I enable Offline Files?
Win2K Pro includes support for Offline Files, a caching system in which copies of documents residing on a file server also reside on your local hard disk. When you log off the file server, you still have access to the file you're working on—and it's available using the same path information you would use to connect to the file on the file server. Offline files simplify the use of laptop clients and help ensure that all the files you need are with you—not back in the office. Offline files also prevent data loss that results from failed network connections.
To make a folder or drive available offline, right-click the folder or drive in Windows Explorer or My Network Places and choose Make Available Offline from the context menu. The first time you attempt this procedure, Win2K will need to copy all the requested files from the server to your computer, so be prepared to wait. After the process has completed, however, synchronization doesn't take long. Windows Explorer uses a recycling icon to display any folders that are available offline. By default, your offline files will synchronize when you log on or off the network, but you can perform this synchronization at any time by choosing Synchronize from the Tools menu in Windows Explorer or My Computer.
How do I view the details of my current system configuration?
If you want complete information about every piece of hardware and most of the software in your computer, go to the System Information icon, which resides in the System Tools section of Computer Management. The information that this feature provides is generally accurate. Whenever I use the System Information tool to perform an inventory on a Win2K system, the hardware inventory almost always matches my observations.
You can transfer this information to someone else (e.g., for troubleshooting purposes) by saving the file. To do so, right-click the System Information icon and choose the appropriate option from the context menu. If the other person uses Win2K, you can (and should) save the data as a system information file, which the other user can import to his or her computer and view just like local data. If the other user doesn't use Win2K, you can save the data as a text file—but you'll get a huge text file that is difficult to scan quickly.
How do I get performance data?
Win9x offers rudimentary system-performance tools. Win2K offers many more, and they can be useful for troubleshooting. Although I don't have room to completely list all objects and their counters, I can describe how to start gathering data.
Click the Performance applet in Administrative Tools to open the System Monitor tool. At the top of the screen, you'll see a row of icons. To add a counter, click the plus-sign (+) icon. In the Add Counters dialog box that opens, you can choose the category of information you want to monitor (e.g., memory, processor time), then choose counters within those object categories. If your computer is on a network, you can also choose to monitor remote Win2K or NT computers. This functionality is handy for evaluating system stress without adding a local instance of the System Monitor to that stress.
Win2K lacks an important tool that Win9x offers: a Resource Meter tool that shows current resource usage. The closest tool you'll find is Task Manager, which you access by pressing Ctrl+Alt+Del and choosing Task Manager from the Windows Security dialog box that appears. Task Manager is more useful for killing runaway processes than Win9x's Close Program tool is. However, although Task Manager displays a short history of CPU and memory use when maximized, as Figure 7 shows, it shows only current CPU use when minimized.
How do I read a log of system events?
Win2K records important events in Event Viewer, which resides in the Administrative Tools folder. Win2K divides the event log into three sections: Application, Security, and System. If something goes wrong with your computer, perusing these logs can sometimes give you an idea of the cause. Figuring out which objects send messages to the Event Viewer service and which log those messages appear in can take time. For example, messages regarding suspending a computer come from Win32k (i.e., the Win32 subsystem) and Removable Storage, whereas messages regarding hibernation come from Removable Storage. If you're planning to use the event logs for troubleshooting, you'll need to learn which logs contain the types of events you're interested in monitoring.
When you open the logs, you'll notice that the Security log is empty. By default, Win2K doesn't log security information. To start Security logging, you need to enable a group policy for your computer. From the Local Security Policy applet in Administrative Tools, drill down to Local Policies, Audit Policy, as Figure 8 shows. Right-click a policy, and choose Security from the context menu to selectively enable security events to audit. Don't go overboard, especially for success audits, or you'll end up with so many events in the log that you won't be able to find anything.
How do I view and edit current service status?
Services control much of Win2K. The Services applet in Administrative Tools lets you see the available services, as well as view and edit their start times (i.e., when they start in the boot process). Don't change service start times unless you know what you're doing because changing a start time or disabling a service might prevent your computer from booting.
How do I install the Recovery Console?
The Recovery Console (RC) is a command-line "backdoor" to Win2K. The RC doesn't let you do everything you can do from the GUI—for example, you can get to data only in the system directory, not on just any disk partition—but it lets you do a fair amount to fix a broken system. (You can also break a fixed system, so be careful when you use this tool.) To install the RC, insert the installation CD-ROM and type
assuming that D is your CD-ROM drive. A dialog box informs you that you're about to install the RC; when you click OK, Setup copies the files to your computer. Installing the RC adds the RC to the boot menu options. For more information about using the RC, see "Windows 2000 Server Recovery Tools," Winter 1999, and Zubair Ahmad, "The Windows 2000 Recovery Console," http://www.win2000mag.com/, InstantDoc ID 7250.
Creating a Personal Management Toolkit with MMC
You've probably noticed that to use many of these tools, you're required to open and close a lot of dialog boxes. What if you could assemble the tools you use most often into one dialog box? Microsoft Management Console (MMC) provides such functionality. MMC is an interface for any snap-in tools that Microsoft develops, but it also works with snap-ins that third-party companies develop. To see the basic framework of the tool, go to Start, Run and type
You can add tools to the console in any combination. For example, I mentioned earlier the need to set a group policy to enable security auditing. To do that, I can use the Group Policy snap-in. I open MMC, then choose Add/Remove Snap-In from the Console menu. Then, I click Add to open a list of available snap-ins, scroll down to find Group Policy, and specify that I want to use this tool on my local computer. When I close the dialog boxes, I've got the Group Policy snap-in. I can add any snap-ins that I need, and I can skip any snap-ins that I don't need. Then, I can save that console by choosing Save As from MMC's Console menu.
After you add a snap-in, you don't need to use its complete functionality. Suppose you want to use only the security settings from the Group Policy snap-in. To trim the toolset to your needs, simply return to the Add/Remove Snap-In dialog box, select Group Policy, and go to the Extensions tab. Clear the Add All Extensions check box, then clear the options that you don't want. (Unfortunately, you don't have the option to Clear All; therefore, you must start with all options selected.) Choose your Security settings, and when you return to MMC, you'll have a much more streamlined Group Policy tool.
Win9x Is a Good Head Start
Much of the Win2K interface will look familiar to power users, but Microsoft has rearranged some elements, and many of the new features offer far more options than Win9x offers. With a little practice, you can find the tools you need, determine how to use them, and create your customized MMC toolkit.
- In the article "Win2K Pro for the Win9x User," the command for installing the Recovery Console (RC) appeared as D:\i386\winnt32\cmdcons. This is incorrect. The correct command syntax is D:\i386 winnt32 /cmdcons. We apologize for any inconvenience this error might have caused.