Issues Debugging Managed Code in WinDbg with SOS and PSSCOR2 (e.g. "Failed to request ThreadStore")

Yesterday I found myself back in "WinDbg-land" after a long, long time (since 99% of my debugging is performed in development environments using Visual Studio).

However, I couldn't get the managed code debugging to work in WinDbg. I initially tried SOS and later PSSCOR2, but they both refused to produce anything even remotely helpful.

For example, when I ran the "!threads" command, WinDbg simply reported the following:

Failed to request ThreadStore
Similarly, when I ran "!eeheap", the following message was displayed:

Unable to get system domain info
I have to admit, I was completely stumped. My initial research on the "Failed to request ThreadStore" error suggested that this problem occurs when the symbols are not loaded. However, even after purging my local symbol cache and downloading fresh copies from http://msdl.microsoft.com/download/symbols, I still got the same errors.

Consequently I sent an email out last night to one of the debugging groups. Fortunately, I didn't have to wait very long for a response.

This morning, Sukesh Ashok Kumar, a Support Escalation Engineer in the PSS group, told me to check a few things:

• Use "lm v m mscorwks" and see if the symbols are loaded
• Use .cordll and see if the right mscordacwks is loaded
• Use correct architecture of extension sos/psscor2

As I mentioned before, I purged my symbol cache yesterday and downloaded fresh copies from the Microsoft public symbol server, so the first suggestion didn't seem to be the problem. However, I ran "ld mscorwks" anyway and verified the symbols were loaded as expected.

Read more: Random Musings of Jeremy Jameson

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