Just to make sure I'm understanding correctly: when you restart your machine and profile your application the first time, everything is fine, but when you profile a second time, the profiler hangs?
Can I please double check--is this website running in IIS or via the web dev server? Are there any errors related to either in Event Viewer?
If you try profiling a very simple website, does the problem still occur?
If you reinstall version 8.5 (ftp://support.red-gate.com/patches/ANTS ... 5.0.12.zip
) does that work again as expected?