Cannot obtain value of local or argument as it is not available at this instruction pointer possibly because it has been optimized away

Question

Visual Studio 2010 kills  there is no other word  data in one of the arguments of the function in the unsafe block  What could cause this error  The following message shows by the debugger    Cannot obtain value of local or argument as it is not available at this instruction pointer  possibly because it has been optimized away

User · Answer

Check to see if you have a Debuggable attribute in your AssemblyInfo file. If there is, remove it and rebuild your solution to see if the local variables become available.

My debuggable attribute was set to: DebuggableAttribute.DebuggingModes.IgnoreSymbolStoreSequencePoints which according to this MSDN article tells the JIT compiler to use optimizations. I removed this line from my AssemblyInfo.cs file and the local variables were available.

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When I was faced with the same problem I just had to clean my solution before rebuilding  That took care of it for me

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In Visual Studio 2012   Go to the project properties -  Debug -  Uncheck  Enable the Visual Studio hosting process

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Had the same issue before with a WPF application and all the solutions here did NOT solve the issue  The problem was that the Module was already optimized so the following solutions DO NOT WORKS  or are not enough to solve the issue      Optimize Code  checkbox un-Checked  Suppress JIT optimization on module load  checked Solution configuration on DEBUG   The module is still loaded Optimized  See following screenshot      To SOLVE this issue you have to delete the optimized module  To find the optimized module path you can use a tool like Process Hacker   Double click your program in the  Process panel  then in the new window open the tab   NET Assemblies   Then in the column  Native image path  you find all Optimized modules paths  Locate the one you want to de-optimize and delete the folder  see screenshot below     I blurred my company name for obvious reasons   Restart your application  with check box in step 1 correctly checked  and it should works   Note  The file may be locked as it was opened by another process  try closing Visual Studio  If the file is still locked you can use a program like Lock Hunter

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In visual Studio 2017 goto Debug- Option then check Debugging- general-  and check this option

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In Visual Studio 2017 or 2015   Go to the Solution right click on solution then select Properties-  select all the Configuration-  Debug then click OK  After that Rebuild and Run this solution worked for me

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Also In VS 2015 Community Edition  go to Debug- Options or Tools- Options  and check Debugging- General- Suppress JIT optimization on module load  Managed only

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In my case  I was working on a web api project and although the project was set correctly to full debug  I was still seeing this error every time I attached to the IIS process I was trying to debug  Then I realized the publish profile was set to use the Release configuration  So one more place to check is your publish profile if you re using the  Publish  feature of your dotnet web api project

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I had the same issue  Tried all the above and found I also had to delete everything inside  PROJECT ROOT  bin Release netcoreapp2 2 and  PROJECT ROOT  obj Release netcoreapp2 2 for my project  Its definitely releated to publishing because although I use Deployment tools   bitbucket on my Azure Web App  I did try the Build    Publish    Publish to Azure because I wanted to inspect which files were actually deployed

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I just ran into this and I was running under Release build configuration instead of Debug build configuration   Once I switched back to Debug my variable showed in the watch again

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Regarding the problem with  Optimize code  property being UNCHECKED yet the code still compiling as optimized  What finally helped me after trying everything was checking the  Enable unmanaged code debugging  checkbox on the same settings page  Project properties - Debug   It doesn t directly relate to the code optimization  but with this enabled  VS no longer optimizes my library and I can debug

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I have faced the same issue and the solution for me is change Solution Configuration from Release to Debug  Hope it helps

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If you compile with optimizations enabled  then many variables will be removed  for example   SomeType value   GetValue    DoSomething value     here the local variable value would typically get removed  keeping the value on the stack instead - a bit like as if you had written   DoSomething GetValue       Also  if a return value isn t used at all  then it will be dropped via  pop   rather than stored in a local via  stloc   and again  the local will not exist    Because of this  in such a build the debugger can t get the current value of value because it doesn t exist - it only exists for the brief instant between GetValue   and DoSomething        So  if you want to debug    don t use a release build  or at least  disable optimizations while you debug

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As an additional answer for those experiencing this issue when debugging an Azure websites  web app   When deploying from GitHub  for example  the code is compiled in Azure server optimized by default   I tell the server to compile in a debuggable way by setting SCM BUILD ARGS to  p Configuration Debug  but there are more options  See this  http   azure microsoft com blog 2014 05 08 introduction-to-remote-debugging-on-azure-web-sites-part-3-multi-instance-environment-and-git

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I found that I had the same problem when I was running a project and debugging by attaching to an IIS process  I also was running in Debug mode with optimizations turned off  While I thought the code compiled fine  when I detached and tried to compile  one of the references was not found  This was due to another developer here that made modifications and changed the location of the reference  The reference did not show up with the alert symbol  so I thought everything was fine until I did the compilation  Once fixing the reference and running again it worked

User · Answer

Go to Project Properties and under Build Make sure that the  Optimize Code  checkbox is unchecked    Also  set the  Debug Info  dropdown to  Full  in the Advanced Options  Under Build tab

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For web applications there is another issue which is important and it is selecting correct  configuration during application publish process   You may build your app in debug mode  but it might happen you publish it in release mode which omptimzes code by default but IDE may mislead you since it shows debug mode while published code is in release mode  You can see details in below snapshot

[c#] Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away

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