If you encounter various errors when runing shared MS-DOS based database applications on your network, such as:

      The file is in use

      The file is already open

      Unable to write to drive <X:>

      The network drive <X:> is no longer available

these applications do not understand the Windows NT file locking mechanisms.

If you can't upgrade these applications, use regedt32 to navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters

Edit or Add Value name, the following three (3) REG_DWORD values:

CachedOpenLimit - set the data value to 0 to prevent the caching of previously open files.

EnableOplocks - set the data value to 0 to turn off opportunistic file locking.

autodisconnect - set the data value to 0xFFFFFFFF to prevent the client workstation from being disconnected due to a time out.