Unable to debug managed code using visual studio 2013 (“Cannot evaluate expression” error - am using debug build) (Note that VS 2012 works)

Question

I have .net application (GUI as well as PowerShell) built against 4.5. My OS is server 2012. When I attach my application to 2013 visual studio, the debugger is not working

Answer 1

We had this problem with PostSharp extension version 5.0.32 with VS2013 Update 5.

Our workaround was downgrade PostSharp extension to version 4.3.19 or disable it.

Answer 2

If you are facing the same issue, please look at http://weblog.west-wind.com/posts/2013/Nov/21/Visual-Studio-2013-Could-not-evaluate-Expression-Debugger-Abnormality for details.

Here is the answer which solved for me:

I have set the flag "use managed compatibility mode" in Tools | Options | Debugger | General.

For details, take a look at the link as he explained it nicely as a story :)

Am happy it worked, otherwise I just had to load project in vs 2k12 just to debug it which is annoying.

EDIT on 12th June 2014

I have updated my dev environments with visual studio 2013 update 2 (http://www.microsoft.com/en-us/download/details.aspx?id=42666) (as per Maria's suggestion below) and removed "using managed compatibility mode". I will be testing my apps (ps cmdlets, gui, services) and update you in couple of weeks if the debugger is ok for me.

EDIT on 26th June 2014

I have tested my apps and luckily for me everything is working nicely :). Even the debugger is doing pretty good job with new async/await model. So, see if you can upgrade to 'update 2' - hopefully this works in your environment too?. Thanks to Maria and debugger's team!

Regards.

Answer 3

We have released a fix for the issue you are describing in Update 2 CTP 2 of Visual Studio -
Please let me know if that doesn't resolve your issue!

Thanks! Maria - Visual Studio Debugger

Answer 4

You can resolve this error by applying below points

Sol 1:

1) Restart visual studio and re-open your project.
2) Open your project bin directory and delete DLL of that code where your debugger is not working properly.
3) Then again add DLL reference in the bin directory.
4) Remove all breakpoints.
5) Build project.
6) attach with one w3wp.exe process in attach to process window
7) Enjoy your problem has been resolved.

If above solution is not working then you can try solution that has been provided on bellow link
http://weblog.west-wind.com/posts/2013/Nov/21/Visual-Studio-2013-Could-not-evaluate-Expression-Debugger-Abnormality

Answer 5

Please note that while the accepted answer probably will fix the problem for now, it's best to be aware of the drawbacks of this solution. Making this change will make VS 2013 use the older style debugger for all you projects. It is a global setting. There are other ways to locally change this for a single project. Please read here for more info on this:

http://blogs.msdn.com/b/visualstudioalm/archive/2013/10/16/switching-to-managed-compatibility-mode-in-visual-studio-2013.aspx

Answer 6

Set AutoEventWireup="true" on aspx header file. This will turn debug mode on.