Index.dat File in the History Folder May Become Very Large

If a user name contains the number sign (#), regardless of where the number sign appears in the user name, the Internet Explorer history file associated with that user may become corrupted. This problem occurs whether the user logs on locally or logs on to a Microsoft Windows NT-based domain. In addition, the Index.dat file may expand up to several megabytes in size.

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Internet Explorer service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.