OK, so whats the deal with Outlook and PST file size limits?

Yeah, we get asked the same question quite alot, especially after someone’s email account has just hit the limit and locked up.

Alright, just to make this as clear as possible, here is how the Outlook file size limits work.

Prior to Outlook 2003, PST files used the ANSI format, this gave them a file size limit of 2GB. From Outlook 2003 onwards, the PST files used the Unicode format, providing a filesize of 20GB.

BUT, this just applies to PST files that connect to Exchange/POP3 etc. It does not apply to Exchange PST files that are IMAP based. If you are using Outlook and connecting to an IMAP server, the 2GB limit still applies. This was only fixed in Outlook 2007, which now should allow for 20GB IMAP limits.

It is definitely very confusing. Also, with the size of modern email accounts, the 20GB limit may not seem all that great. Well we will talk more about that later. But for now just remember to keep an eye on your PST filesize.

If your PST files are approaching the MAX size, it may just lock up and stop receiving email. In some cases there is no error message provided.

To view your PST files in Outlook: File -> Data File Management

If you do have a locked, corrupted or oversized PST file, give the following download a try: PST Recovery – Free Download.