Split Outlook Large PST files Quickly

Solution to Unable to Expand the Folder Error in Outlook

Microsoft Outlook provides a plethora of flexible features. For the convenience of a user, this mailing application has a feature which lets you store more emails and items in your folder by letting you add other mailbox in the folder list of Outlook. However, often this feature comes out as a problem to the user in the form of error message 'unable to expand the folder'. If this error not curbed within time, it grows and is followed by consequences like inaccessibility of data from the folder, more error messages and so on.

Generally, the above mentioned error message mostly occurs in this form:

“Unable to expand the folder. The set of folders could not be opened”

Basically, the aforementioned error message mostly happens due to these reasons:


  • One reason is that you might not have enabled the Folder Visible option

  • While other reason which is mostly supposed to be the main cause behind this is the exceeding size of PST files. This very error mostly could be observed in the earlier MS Outlook versions that have a fixed PST size limit of only 2GB.

Solution to Unable to Expand the folder Issue

The solution to fix the error message forever is not that very hard. All that is required is to suppress or do away with the above mentioned causes. Below you will find how to do it exactly to eliminate the error completely off your system.

As mentioned, the first cause can be not enabling the Folder Visible option. To do this, you have to do the following:

  • Begin with right clicking that particular PST that you have to access and click on Properties option from the menu.
  • Go to a tab labeled as Permissions and now check the Folder Visible Option in order in enable it and click on OK.

Most of the time, you will be able to fix the error by following the above steps. But if you are still getting unable to expand the folder error, then the cause is severe and is occurring due to oversized PST. Reduce the size of the file by archiving it, cutting the file or by transferring the file of the PST into a new PST file. The manual process however is very time consuming. Moreover, it is not a good solution for the non-techs or novices. For them, it would be beneficial to use third party PST repair tool. The tool will automatically in no time will resolve this error by dividing and cutting big PST files.