Outlook may become unstable for the following reasons:
The good news is that because the OpenProtocol connector replicates data to the messaging platform, any profile corruption or Outlook related issue can be recovered by simply recreating the profile or removing the account from the profile.
As such, the simplest solution is to follow the Microsoft recommendation outlined in the "more information" section of this article.
Alternatively, the issue can be diagnosed by disabling any Outlook Extensions or Add-ins listed under Outlook's Options menu.
The extensions can be re-enabled one at a time, to verify which extension is causing issues.
Please see Microsoft's Article: http://support.microsoft.com/kb/2391896