In Outlook 2003 to 2013, the prompt “Cannot open your default e-mail folders. The information store could not be opened” keeps appearing. However, there’s no reason to panic. Although it might sound like a significant error, this is something that can be easily fixed.
Microsoft claims that the primary cause of this problem is a corrupted Navigation Pane settings file, although instances of this happening are in the minority. A good indication that the file is corrupted is when the file size is 0 KB. The exact cause of this phenomenon is unknown. It appears to be a universal problem, potentially affecting all versions of Microsoft Outlook from 2003 to the latest 2013 edition.
In addition, if you are running Outlook in compatibility mode, it could be the cause of the error. It’s also possible that the Outlook data file (.pst or .ost) has been deleted or corrupted due to incorrect installation of Outlook.
Whatever the reason might be, just follow the steps below and the problem will be fixed.
Method 1: Repairing the Outlook data file (.ost or .pst)
Repairing the .ost file has done the trick for some users; in order to repair the .ost file, open the search dialogue box by pressing the Windows and F keys
Now type “exe” in the search box at the top right corner and press enter.
Now select the “Local Disk: C” from the left panel and select the Program files.
Upon selecting the program files, go to the search box and type “Scanost.exe” again.
Now that you have located the SCANOST file, open it. You will be presented with a pop-up. Click OK.
The ‘OST Integrity Check’ setup will open up. Check in the ‘Repair errors’ box and click on ‘Begin Scan’.
Scanning will now take place; depending on the number of files and errors, this could take a while to complete.
Close all the Windows, the .ost file has been successfully repaired.
Method 2: Running Outlook in Compatibility Mode.
Switching off the compatibility mode is quite easy. Navigate straight to the Local Disk: C > Program Files > Microsoft Office > Office XX > Outlook.exe.
Now, right-click on the “Outlook.exe” file, click on “Properties”, and navigate to the “Compatibility” tab.
Now, simply uncheck the “Run this program in compatibility mode” box.
Click on “Apply.” You have successfully turned off the compatibility mode.
If this issue is experienced on an exchange email account configured on your Outlook, then try the following steps:
If you are running a Windows Server and/or a firewall, try disabling the firewall and connecting the server directly without any firewall.
Once the issue is resolved, you will need to reconfigure your firewall to allow Exchange to sync.
If the issue is not resolved by disabling the firewall, then create a new mail profile from Outlook and reconfigure your account.