Steps to reproduce: Press ctrl-F or ctrl-H to open the search box. Select "Use Regular Expressions" (.*). Type the caret character (^).
Outcome: Visual Studio hangs and Task Manager shows devenv.exe to be happily chewing through memory.
Visual Assist X Version 10.7.1949.0 Built 2013.07.25 Microsoft Visual Studio Professional 2012 Version 11.0.61030.00 Update 4 100% reproducible in VC++ for VS2012 and VS2013.
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New information:
Disable Visual Assist through the menu options, carry out the regular expression search for ^ (successfully), re-enable Visual Assist through the menu options and it crashes with the same symptoms as described above.