An Outlook personal folder (.pst) file that exceeds the 2 gigabyte (GB) size limit is unusable.
Download PSTsize, authored by Harry Bates, to report the when a .pst file exceeds the limit that you set.
PSTsize.exe is designed to run in a logon script. It recursively searches a users mounted .pst files by reading the location from HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles.
PSTsize checks to see if the path is valid and checks the size of the file. The output is configurable.
To get help, open a CMD prompt and type: pstsize /?
NOTE: See OL: Oversized PST and OST Crop Tool.