Today I had to resolve a problem with Outlook 2010 not starting. The user was greated with the message:
“Cannot open your default e-mail folders. The information store could not be opened.”

I found the Outlook.exe file was in XP compatibility mode.

To check:
1. Open My Computer and navigate to c:\Program Files\Microsoft Office\Office X\ or on 64-bit, C:\Program Files x86\Microsoft Office>Office X. (Where X is a version number)
2. Right click on Outlook.exe and click on Properties. Click on the ‘Compatibility’ tab and uncheck any compatibility mode options.
3. Retry.

Hope this helps with your problem….