Back in October 2006 I wrote an article which covers troubleshooting problems related to WebResource.axd. A few months down the track, and the article has had a lot of hits, a few comments, and a few external links - I can only conclude that a lot of you out there have had major problems with WebResource.axd!
I wrote the article as a result of problems when deploying the project I was working on at the time, and it seems that I was 'lucky' enough to need to make changes or to verify the configuration for a lot of the different areas which can cause WebResource.axd issues - Missing compression exclusion, issues with compression module , Missing MachineKey / ValidationKey, incorrect IIS setup (specifically the Application extension mapping) to be more specific. As a result, the article covers a much wider range of troubleshooting options than anything else out there.. which is good, as it's exactly why I wrote it!
Anyway, it's always nice to know people find these things useful. If you got some value from the article, please add a comment or drop me a mail to let me know, feedback like that really helps with motivation to write more articles.
Link: Troubleshooting issues with WebResource.axd