In Outlook, the storage limit for a single user's .PST file (the file used as Outlook's message database) is 2 GB. If a .PST file grows to over 2 GB, it can become damaged and some mail items may be lost.
Users of Office XP Service Pack 1 and higher will simply get errors and not be able to add or receive new mail items. (The error usually states that one should permanently delete items to reduce the amount of data in the file, but it is probably better to archive older items to a separate .PST file rather than delete them outright.) Users of earlier versions of Outlook will get no warning, however, and the file will be damaged.
If you're forced to use .PST files (for instance, in a remote scenario) and run into this problem, or have older .PST files over the 2 GB boundary that need to be recovered, one solution is to use a Microsoft utility called PST2GB.
This tool uses a fairly radical approach to "repairing" such a file: it forcibly truncates the file at the 2 GB boundary (actually, slightly below it) and makes it readable again. Unfortunately, this means that everything after the truncation will be lost. If you can suffer the loss of the data at the end of the file (which tends to be spurious), you can use this to restore the file to working order and extract the messages within.
Note that in order for PST2GB to work, you must have at least 2 GB free space on the drive itself. It is also probably a good idea to work on backup copies, not originals, since the resulting file will be truncated; if you come across another way of retrieving the rest of the messages, it would be good to have them available in some form.
About the author: Serdar Yegulalp is editor of the Windows 2000 Power Users Newsletter and a regular contributor to SearchExchange.com.