When you search in SharePoint 2010, you may get the following error:

Error

Internal server error exception

Troubleshoot issues with Microsoft SharePoint Foundation.

Correlation ID: de2996f1-a6c9-42fb-a6da-e5fc7d769069
*NOTE You will have a different Correlation ID! Look up your Correlation ID in your log files.

Solution 1:

You will have to install the following hotfix

http://go.microsoft.com/fwlink/?LinkID=166231

For Windows Server 2008 R2, Hotfix for.NET Framework 3.5 SP1 that provides a method to support the token authentication without transport security or message encryption in WCF (http://go.microsoft.com/fwlink/?LinkID=166231).

Solution 2:

Reboot your server(s). Ensure that your search services have started.

Solution 3:

Ensure you dont have any issues with your search databases. Eg. Out of disk space, SQL Alias not present on all SharePoint servers.