When we look at the list of system folders on our Exchange 2000 Server systems, we see several OWAScratchPad folders. What are these folders, and do we need to keep them?

Yes, you need to maintain the OWAScratchPad folders. (The names of these OWAScratchPad folders contain globally unique identifiers—GUIDS—but for simplicity, I've omitted these GUIDS in this discussion.) Your first hint that these folders are important is that they're classified as system folders, which you'll see only when you right-click the Public Folders object in Exchange System Manager (ESM) and choose the View System Folders command. Exchange creates the OWAScratchPad folders when a user adds an attachment to a public folder post. If you delete these folders, Exchange will recreate them.

The trick to keeping these folders under control is knowing that only one scratch pad folder exists per server—that's where the GUID comes from. If you want to find out which server a folder belongs to, open ESM, open the Folders object under the administrative group that contains your server, and right-click the Public Folders node. Choose View System Folders from the context menu, select the OWAScratchPad\{GUID\} item, then select the Replication tab. If no replicas are listed for a scratch pad folder, as Figure 1 shows, that folder belongs to a server that has been removed from your organization and you can safely delete it. By default, your users can add attachments as big as 1MB to public folder items; if you want to increase that size, you need to tweak the folder's storage limit.