Debuging (Evalutation) stops working at times - Unable to evaluate the expression - by Shiv Kumar

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  Fixed<br /><br />
		This item has been fixed in the current or upcoming version of this product.<br /><br />
		A more detailed explanation for the resolution of this particular item may have been provided in the comments section.

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ID 622525 Comments
Status Closed Workarounds
Type Bug Repros 8
Opened 11/17/2010 3:16:29 AM
Access Restriction Public


I'm on Windows 7 64bit and am using VS.NET 2010 Ultimate

Never had a problem with VS.NET 2010 until recently. And the problem I am having is that when I create a new console app and am not able to:
1.  Evalutate any variable values
2. Hover over any variables and see their values
3. Use the immidiate window to get any values. I see a message -"Unable to evaluate the expression"

The debugger stops and the break points as expected but the above does not work.

If I switch the Project Build platofrm target property from x86 to Any CPU, then everything works as expected. Switching it back to x86 gives to the same behavior as explained above.

Other project types exhibit the same behavior sometimes. I have a new ASP.NET MVC project that are created and it exhibits the same behaviour. In fact with this project I am unable ot debug no matter what the build settings are.

Older console app projects have this problem as well (they used ot work just fine earlier).
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Posted by volatiless on 1/20/2011 at 9:35 AM
I have uninstalled AsyncCTP and MVC 3 (not RC, RC was never installed) and still get same issue.
Posted by Microsoft on 12/10/2010 at 3:29 PM
Hi Shiv,

Do you have a reproduce project and steps to help us reproduce the problem? Without reproducing, it is hard for us to figure the reason.

As you said, you can also reproduce the problem in a sample console project. So I think the problem may not be MVC related?

Jeffrey Tan
Visual Studio Debugger Team

Posted by Laurent Kempé on 11/23/2010 at 2:08 AM
Have a look to the workaround tab to see how to avoid this issue
Posted by Laurent Kempé on 11/23/2010 at 1:14 AM
I confirm that it is linked to ASync CTP + ASP.NET MVC 3!

I didn't realized that Async CTP was installed has an update, so you need to uninstall as an update.

I will blog about it.
Posted by Steve Hansen [2sky] on 11/22/2010 at 5:21 AM
I think it is related to ASP.NET MVC3 + Async CTP
Posted by Microsoft on 11/22/2010 at 12:03 AM
Hi, I installed ASP.Net MVC 3 RC which I downloaded from

I still unable to repro this issue. If you could get back to me at your earliest convenience with information I request, we will be able to make headway towards a resolution. I look forward to hearing from you.
Posted by dwsqAnonymous on 11/19/2010 at 11:06 AM
I wonder if this has anything to do with the new Razor Intellisense supplied with MVC 3 RC?
Posted by Laurent Kempé on 11/19/2010 at 5:04 AM
I uninstalled/re-installed VS2010 Ultimate on my Windows 7 Ultimate 64bit and the problem is still here!
Posted by Laurent Kempé on 11/19/2010 at 12:42 AM
Shiv: your re-installation of VS2010 solved the issue ?

I'll try to do a video, but I am not sure it will help anything your bug entry is very well documented
Posted by Shiv Kumar on 11/18/2010 at 9:10 PM
laurent since you can reproduce this problem, can you make a video and post it here so the folks can see?
Posted by Shiv Kumar on 11/18/2010 at 9:09 PM
Yup, I tried that too since that was the last thing I installed before I started having this issue.
Posted by Laurent Kempé on 11/18/2010 at 2:51 PM
I uninstalled mvc 3 rc, webmatrix and it still doesn't work
Posted by Shiv Kumar on 11/18/2010 at 12:49 PM
You know I thought about making a video but unfortunately I did not. I uninstalled and re-installed VS.NET 2010 (which is quite a job actually) because I just couldn't continue to work like this as the project I was currently working on (ASP.NET) just stopped being able to be debugged.

I realize that if you can re-produce it's difficult to fix, but I think the big clue should be the fact that changing the target platform fixes it most times.
Posted by Laurent Kempé on 11/18/2010 at 11:53 AM
I can reproduce the same bug on my env. using the "Steps to reproduce".

I have an mvc 2 project which has the same issue. But I have another which is WPF which is working.

I have webmatrix rcand mvc 3 rc installed
Posted by Microsoft on 11/17/2010 at 7:56 PM
Hi Shiv,

Thanks for reporting this issue. In order to fix the issue, we must first reproduce the issue in our labs. We are unable to reproduce the issue with the steps you provided.

Please give us a video of this issue so that we can conduct further research.

It would be greatly appreciated if you could provide us with that information as quickly as possible. If we do not hear back from you within 7 days, we will close this issue.

Thanks again for your efforts and we look forward to hearing from you.

Microsoft Visual Studio Connect Support Team
Posted by Microsoft on 11/17/2010 at 3:20 AM
Thank you for your feedback, we are currently reviewing the issue you have submitted. If this issue is urgent, please contact support directly(