MS Outlook is considered as one of the most preferred Email application that is widely used for receiving and sending mails. To store all the sent, received and created information, MS Outlook creates a PST File. It can be termed as a storehouse of MS Outlook to save email items like contacts, calendar events, journal, tasks, etc. Personal Storage Table or PST is created in two formats, namely UNICODE and ANSI. ANSI format supports the older versions of MS Outlook (97, 2000 and 2002). It has a physical size limit of 2GB only that means it cannot store data more than 2GB. If data limit cross the 2GB mark then the ANSI PST will become corrupt and becomes inaccessible to the user. Increased file size causes corruption in a PST file. Whenever a ANSI PST gets corrupt it behaves in a strange way and looser looses all the valuable data which is stored inside the file. UNICODE format supports the recent versions of the MS Outlook (2003 onwards). It has a size limit of 20GB in Outlook 2003 and 2007 and 50 GB in Outlook 2010 onwards. Generally speaking, UNICODE PST format doesn’t not cross the default files size but if it does it can lead to corruption. MS Outlook shows abrupt behavior in its functioning, it is prone to frequent crashing and may become slow. Compact PST is the ideal way to counter MS Outlook corruption. Users should act smart and compact the file before it reaches the threshold level. You can manually compact the PST file by following these steps: Launch MS Outlook Delete unwanted items from PST file Select File > Data File Management. A dialog box ‘Account Settings’ will appear Select Data Files Select PST File Click Settings. A dialog box showing ‘Personal Folders’ will appear Click Compact Now. MS Outlook will automatically clean up the extra space When it is complete. Click OK This way you can easily manage the oversize issue of the database files. But if the oversize file is still a cause of concern, it is advised that you should use a third party PST Compact and Compress Tool.