Outlook Data Files Will Not Open

(Last Updated On: February 26, 2018)

Problem description for outlook data files will not open

When tried to create, close and reopen a data file using Office 365 the .pst file will not open. The error window saysA dialog box is open. Close it and try again.”

This may happen even if you see no dialog boxes are evidently open and fails even if you try again accomplishes nothing.

Had reported multitude of problems due to the poor implementation of .pst files in all versions of Outlook, but I have never had this particular problem with any previous versions. There seems to be no way to open a .pst file using Office 365 after a .pst is closed.


In general, the best practice to deploy a PST file is to import the PST into an outlook program rather than double clicking  it to open the emails.

Even if you have an Outlook program running efficiently, the best method is to change and add the data file through the account settings.

Email Account settings

Email Account settings

Step2: select Data settings

Outlook Data settings

Data settings

Using the above image, you can understand from where a PST file can be added.

This is a correct way to add any PST file to Outlook.

In case if you have any other issues in managing a DATA files like PST’s and OST’s or to recover the forgotten password on PST’s we have our experts who can deliver you the output.

We need to analyse the size of the PST’s and check the reason why you are getting this issue.

In OUTLOOK 2010 and before, the size limit for a PST is 2GB .The size can be still increased using registry techniques depending on the requirement.

In OUTLOOK 365 and 2013, it is defined as 20GB but can be extended up to 50GB as per the resources.

The larger PST handling apparently needs the High RAM to handle.

Other wise System process will slowdown and OUTLOOK loads slowly.