I had an issue where users are getting "Access Denied" even though they shouldn't. It turned out to be related to custom code and fixed in the end, but there was a lot of guesswork involved.
Is there any way to troubleshoot Access Denied errors without guessing all the time? Surely, something somewhere throws the ThreadAbort/UnauthorizedAccessException, can I get the Stacktrace of that or get SharePoint to emit more logfiles?
I know of ways to handle it once I know where the issue is (SPSecurity), but if all I have is an Access Denied error and possibly 20 different places to look, it becomes tedious.