+ 0 Votes Which Outlook? Mehul Bhai 4 years ago Which Microsoft Office Outlook Version you are using? There is a limit to the size of PST file. You cannot extend it. You can add more PST files in Outlook and distribute the mails between them in such a way that the size of all the PSTs remain below the size limit, otherwise the mail database will get corrupted. + 0 Votes Answer joebloggs1010101 4 years ago In Outlook 2000 the maximum .pst file size was limited to a 2 GB (actually 1.933 GB). If this limit is reached or exceeded, retrieval of data within the .pst file can be difficult if not impossible. In Outlook 2003 and 2007, the default maximum size is 20 GB, as set in the registry; though unicode PSTs are supported up to 33TB. When interfacing with ANSI .pst files in Outlook 2003 and 2007, the 2 GB limit remains in effect.To change the size:http://support.microsoft.com/kb/832925/ + 0 Votes Make sure you're not using FAT32 on the drive too.. cmatthews 4 years ago ..then you'll have another limit - the 4 gig FAT file size issue:http://support.microsoft.com/kb/314463 + 0 Votes PST file size imran.salamat 4 years ago if you use single PST File then make sure that your INBOX size never go up to 2 GB. create saperte folders in your PST and transfer the emails from INBOX to other folders. Remember ( the custom folders which you create should be out of INBOX folder. + 0 Votes Wrong Mehul Bhai 4 years ago What you mentioned is true for Outlook Express 6 and not Microsoft Office Outlook as Microsoft Office Outlook does not have a seperate PST file for Inbox as does Outlook Express 6 so as to recognize/determine the size.