Users of Outlook Express 5.5 or 6 who have applied the security patch outlined in Microsoft Knowledge Base article...
330994 may notice a file appearing on the desktop with the name ~ -- that is, a single tilde character. Some users are inclined to blame viruses or spyware; even though the file can be deleted, it often reappears on its own for no apparent reason.
The patch is designed to protect against a vulnerability that would allow a malicious third party to execute code on the computer. However, it makes another change: it causes backup copies of the address book (which are generated automatically by Outlook Express whenever something is added or changed) to be renamed to ~. (The default name of the backup file is <username>.wa~, where <username> is the name of the current user.) The renamed file appears in the same directory as the shortcut used to launch Outlook Express. Most often this is the desktop, which is how the file winds up residing there.
The ~ file can be deleted without any ill effects, but this will leave the user without a backup copy of the OE address book. A better solution is to simply move it to another folder or offline. To forcibly redirect where the ~ file is created, edit the shortcut used to start IE and change the Start In field to another folder (such as C:\). The next time OE is started, the ~ file will appear there rather than on the desktop.
Microsoft has admitted it is aware of this problem, but as of this writing (July 2004) there has been no fix offered for it, and it is persistent across all versions of Windows.
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter. Check out his Windows 2000 blog for his latest advice and musings on the world of Windows network administrators – please share your thoughts as well!