Microsoft Outlook locally stores its data such as email messages, calendar, notes, tasks, journals in a Microsoft Personal Folder (.pst). In Microsoft Outlook 97, 98, 2000 & 2002 (XP), PST files are formatted in ANSI (American National Standards Institute) format, and limits the size of Personal Folders .pst files to 2GB. PST files used in Microsoft Outlook 2003 and above versions use the UNICODE format, which has a file size limit that is more than 20 GB.
If any new or altered item increases the size of the PST file over than limit (2 GB), you will not be able to use the .pst file. Even if you delete items from the server mailbox, the .pst file will not synchronize.
Outlook has no built-in way to reduce a PST file that has exceeded the limit. However, Microsoft provides a tool called PST2GB, which you can download to restore the file to operability. But please note, this utility that Outlook provides, truncates the data from between 25 and 50mb and the truncated data is not recoverable. The remaining data under 2GB may be restored.
So it is not helpful to use this utility as you may lose some important Outlook items when it gets truncated. The best pst recovery tool to be used is Remo Outlook Mail Recovery (pst) Software, that can successfully repair 2GB pst. Its intuitive interface guides you all the way through the repair process and restores all the corrupted files from Microsoft Outlook Mails archive file (.pst).
Demo version of the software is available for FREE. Download the demo version first that displays all the folders and the recovered emails inside each folder, which gives you a fair idea about the chances of recovery; however viewing body of each email and recovery of emails is possible with full version only.