In a particular project I recently started the debugger started acting funny. When I\'m debugging and it is paused at a breakpoint, Data Tips don\'t show up, some of the var
This did the trick for me (VS 15 on WIN 10): Debug --> Options --> On General tab check Use legacy C# and VB expression evaluators.
I tried above all suggestions but none of them worked for me. Following resolved my issue -You can try by resetting VS settings. Tools-> Import and Export Settings -> Reset All Settings and then press Next.
[Build] => [Clean solution] has fixed this issue for me when nothing else has worked including emptying the symbol cache.
I had the same problem here (also using windows 8.1 and VS 2013)
To fix it you need to open in VS Tools | Options | Debugger | General and enable the flag [Use Managed Compatibility Mode], which essentially gives you the VS 2012 function evaluation behavior.
Reference: http://weblog.west-wind.com/posts/2013/Nov/21/Visual-Studio-2013-Could-not-evaluate-Expression-Debugger-Abnormality
If you're referring to the 'locals', you can reopen it (while debugging) by going into Debugging -> Windows
It's only accessible during a debugging session.
Try TOOLS->OPTIONS->DEBUGGING->SYMBOLS and hit button Empty Symbol Cache.