The error below is what I get in Edit modus on my start page.
Anybody having a clue what this might be?
I'm using Episerver 5.2.375.236.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: EPiServer.PlugIn.PlugInException: Only UserControls are supported on a tabstrip
When I experienced the same error, the problem was a GUI PlugIn implented as as aspx - and not ascx.
The error disappeared when I entered admin mode /Config/Modules and deactivated the GUI Plugin.