Split Large PST Files
PST Splitter helps to Split Large Files Easily
Fix Unable to expand folder Pst error in Outlook!

MS Outlook is an email client application which stores all data in PST(Personal storage folder). Such that Pst can be said as repository of Outlook as all data like emails, contacts, calendars, notes, tasks and appointments are stored in the PST file. Sometimes while accessing Outlook personal folder, user receive unable to expand folder pst error. The error message is displayed in the following manner:

“unable to expand the folder. The set of folders could not be opened. The file F:/windows/outlook/Microsoft/outlook/username.pst could not be accessed.

The primary reason of occurrence of above error message is due to not setting the “folder visible' option true to use additional PST files. In addition, corruption or damage to the PST file due to virus attack, software malfunctioning or OS corruption, unexpected system shutdown makes PST file inaccessible which leads to error message while trying to open PST file. Beside that oversized pst file is also prime reason to receive this error.


Early version of Outlook like 2003 & earlier has Pst file size limit of 2GB. Once the size of PST file grows above 2GB, Outlook start showing abrupt behavior and several error pop ups. So, Whatever the reason may be, the final result is the loss of your valuable items like emails, contacts, notes, tasks, journals etc. To deal with large PST file, there is need to split large Pst file into smaller one in order to access them easily.


In order to resolve unable to expand folder PST error, you must follow below mentioned steps:


  1. Right click on PST file that you want to share or access and then Go to properties
  2. Then click on permission tab and then check the option to folder visible option and finally click on OK button.

However, if the problem is due to oversized pst file, then you should use third party pst splitter tool to break the large pst files. Using this tool, you can split the oversized pst file into smaller one based on data, size, filename etc. The program uses advance algorithm to resolve “unable to expand folder Pst error” by fixing the oversized Pst file and save data from shrinking due to any damage.



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