An unexpected error has occurred. Web Parts Maintenance Page: If you have permission, you can use this page to temporarily close Web Parts or remove

"An unexpected error has occurred. Web Parts Maintenance Page: If you have permission, you can use this page to temporarily close Web Parts or remove personal settings. For more information, contact your site administrator. Troubleshoot issues with Windows SharePoint Services."

You may receive an error with a SharePoint page that has other web parts. The immediate fix is to delete the web part, but that's not a real workaround. Changing the trust level for the site worked for me.

This is the complete fix:
1. Open web.config file of current web application
2. Find the node that begins 3. Change the trust level from WSS_Minimal to WSS_Medium
4. Save the file
5. Drop to command prompt and execute : iisreset