Reputation: 20324

Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug

Update: A sample project reproducing this bug can be found here at Microsoft Connect. I have also tested and verified that the solution given in the accepted answer below works on that sample project. If this solution doesn't work for you, you are probably having a different issue (which belongs in a separate question).

This is a question asked before, both here on Stack Overflow and other places, but none of the suggestions I've found this far have helped me, so I just have to try asking a new question.

Scenario: I have a simple Windows Forms application (C#, .NET 4.0, Visual Studio 2010). It has a couple of base forms that most other forms inherit from, it uses Entity Framework (and POCO classes) for database access. Nothing fancy, no multi-threading or anything.

Problem: All was fine for a while. Then, all out of the blue, Visual Studio failed to build when I was about to launch the application. I got the warning "Unable to delete file '...bin\Debug\[ProjectName].exe'. Access to the path '...bin\Debug\[ProjectName].exe' is denied." and the error "Unable to copy file 'obj\x86\Debug\[ProjectName].exe' to 'bin\Debug\[ProjectName].exe'. The process cannot access the file 'bin\Debug\[ProjectName].exe' because it is being used by another process." (I get both the warning and the error when running Rebuild, but only the error when running Build - don't think that is relevant?)

I understand perfectly fine what the warning and error message says: Visual Studio is obviously trying to overwrite the exe-file while it at the same time has a lock on it for some reason. However, this doesn't help me find a solution to the problem... The only thing I've found working is to shut down Visual Studio and start it again. Building and launching then work, until I make a change in some of the forms, then I have the same problem again and have to restart... Quite frustrating!

As I mentioned above, this seems to be a known problem, so there are lots of suggested solutions. I'll just list what I've already tried here, so people know what to skip:

Creating a new clean solution and just copy the files from the old solution.

Adding the following to the following to the project's pre-build event:

 if exist "$(TargetPath).locked" del "$(TargetPath).locked"
    if not exist "$(TargetPath).locked" if exist "$(TargetPath)" move "$(TargetPath)" "$(TargetPath).locked"

Adding the following to the project properties (.csproj file):

 <GenerateResourceNeverLockTypeAssemblies>true</GenerateResourceNeverLockTypeAssemblies>

However, none of them worked for me, so you can probably see why I'm starting to get a bit frustrated. I don't know where else to look, so I hope somebody has something to give me! Is this a bug in VS, and if so is there a patch? Or has I done something wrong, do I have a circular reference or similar, and if so how could I find out?

Any suggestions are highly appreciated :)

Update: As mentioned in the comment below, I've also checked using Process Explorer that it actually is Visual Studio that is locking the file.

Upvotes: 199

Answers (30)

AndresRohrAtlasInformatik

Reputation: 538

I had the same problem multiple times but two different approaches helped in conjunction. In all cases one fact is interesting, namely that you can still rename the file. If a file is open by a process it's not possible to rename it. So it must be something else than a simple open file handle.

While compiling a solution that produces IL code Defender totally blocked it even if it contained just a few commands. Even adding the directory to the exclusion list of Windows Defender didn't help. I think the virus scan of Windows Defender has a flaw and goes into an endless loop (or a breakdown?) if a file has a certain unfinished state and it blocks the file. But it never recovers except after a PC restart.
I had the no access bug after I had to kill my solution while Debugging because the Debugger stop button didn't work, or maybe also while doing a regular stop using the stop button, I can't remember anymore. Some dlls seemed to remain locked, no delete possible but I could rename them (??). Then I used 'tasklist.exe' to list all the processes and to my astonishment there was a process still listed with my app's name. Without window. And Task Manager didn't list it in 'Details'. Strange. I could use taskkill /PID:... /F (the /F was necessary) and the process went. After that the compilation succeeded and everything was back to normal. Looks like this exe was holding the DLLs, but in a strange way.

It also occurred much more when Oracle VirtualBox was also running. Don't know whether that has an influence. Could also have a connection to the 'Out of Memory' exceptions that sometimes are reported while VirtualBox is consuming a lot of memory.

Now I use both approaches in conjunction whenever the problem occurs. And it still happens from time to time.

Upvotes: 0

AmirHossein Rezaei

Reputation: 1410

IF YOUR PROBLEM IS NOT SOLVED YET:

Visual studio's error is :

"The process cannot access the file 'bin\Debug**app.exe**' because it is being used by another process."

So ,go to task manager of windows(Ctrl+Shift+Esc),find your application name and force it to close by Endprocces.

Upvotes: 4

Haggis777

Reputation: 46

In case somebody is running into this while trying to debug a Unit Test or Run a unit test I had to kill the following two processes in order for it to release the file:

Upvotes: 1

Wollmich

Reputation: 1646

Re-enabling the Application Experience service of Windows has fixed that kind of problems for me.

See the following links:

I had the problem using Visual Studio 2008, 2010 and 2013 with Windows 7 64-bit.

Upvotes: 0

Peter PitLock

Reputation: 1873

Set another project as startup
Build the project (the non problematic project will display)
Go to the problematic bin\debug folder
Rename myservice.vshost.exe to myservice.exe

Upvotes: 0

BCS Software

Reputation: 1905

Disable "Enable the Visual Studio hosting process"

Upvotes: 5

Sabir Al Fateh

Reputation: 1793

[Solved] Unable to copy exe-file from obj\debug to bin\debug:

I am approaching that you get this error while you was trying to run two windows form one after another such as first loading a form then after sometimes it will automatically disappear and the second form loaded onto the screen.

Basically, you need to close your first form which is running in the background and the main reason behind this error.

To close the first form you have to add these two lines of code in the second form load event handler.

        Form1 form = new Form1();
        form.Close();

This will solve the error perfectly.

Upvotes: 0

Bassie

Reputation: 10390

For me this was being caused by having a command prompt open in the targeted folder (C:\users\username\source\repos\project\project\bin\debug\app.publish).

Not sure why DEBUGGING requires access to the publish folder, but closing the command window solved the issue for me.

Upvotes: 1

Ricardo F.

Reputation: 535

One thing that really helped me was adding the ".exe" on the Debug folder to the Exclusions on my Anti-Virus.

Upvotes: 0

Yee

Reputation: 901

Renaming the .exe and .pub file worked for me, but really tedious. I also face the problem that I could not do editing during a debug session. Finally I went to the Advanced Security Setting Page, as per:

https://msdn.microsoft.com/query/dev10.query?appId=Dev10IDEF1&l=EN-US&k=k%28%22VS.ERR.DEBUG_IN_ZONE_NO_HOSTPROC%3a11310%22%29;k%28TargetFrameworkMoniker-%22.NETFRAMEWORK%2cVERSION%3dV4.0%22%29&rd=true

I un-select then re-select the "Enable ClickOnce security settings" checkbox. It's been problem free for some days now....

Upvotes: 1

Suhan

Reputation: 1434

This helps for me after i remove read only flag from bin directory. http://www.thewindowsclub.com/error-0x80080015-windows-defender-activation-requires-display-name

Upvotes: 0

James Pusateri

Reputation: 166

This is rather commonly caused by Avast.

I can usually run my projects in Release regardless, but when running in debug it would pretty regularly fail.

I just add an exclusion for my projects folder and the problem seems to go away. I assume this might also be cause by other antivirus software.

Upvotes: 1

Greg

Reputation: 126

If none of the above works, and you are developing a console application:

Try typing any character into Program.cs, then delete it. I have no idea why this works, but it seems to resolve 'Unable to copy' problem every time.

Upvotes: 1

Utsav Dawn

Reputation: 8246

I faced the same error.

I solved the problem by deleting all the contents of bin folders of all the dependent projects/libraries.

This error mainly happens due to version changes.

Upvotes: 3

Hassan_Jaffrani

Reputation: 55

Disable antivirus and try. I was also facing that problem... but in my case antivirus was blocking my application when I disabled antivirus it resolved.

Upvotes: 3

NCCSBIM071

Reputation: 1205

I had same problem. It said could not copy from bin\debug to obj.....

When i build web project i found my dll were all in bin folder and not in bin\debug. During publish vs was looking for files in bin\debug. So i opened web project file in editor and look for instances of bin\debug and i found all the dll were mentioned as bin\debug\mylibrary.dll. I removed all \debug from the path and published again. This time vs was able to find all the dll in bin folder and publish succeeded.

I have no idea how this path got changed in web project file.

I spent more than 5 hours debugging this and finally found solution on my own.

This is the right answer.

Upvotes: 1

mattpm

Reputation: 1390

I have found with VS2013 I get this error regularly. Something that seems to work reasonably well is to perform a Rebuild Solution prior trying to run the application. I found that performing a CLEAN sometimes works, but the Rebuild Solution seems to work more consistently.

Upvotes: 0

T.Coutlakis

Reputation: 2771

My solution has nothing to do with versions, processes being locked, restarting, or deleting files.

The problem was actually due to the build failing, and not giving the correct error. The actual problem was a design flaw:

// Either this should be declared outside the function, or..
SomeObject a = new SomeObject(); 

Task.Factory.StartNew(() =>
{
   while (true)
   {
      a.waitForSomething();
   }
});

// ...this should not be called
a.doSomething();

After changing the scope of "a" to outside the function, or not using "a" after Task.Factory.StartNew();, I was able to build again.

This happened when using VS2012 Update 4 on Windows7x64 sp1.

Error message:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(3390,5): error MSB3030: Could not copy the file "obj\x86\Debug\xxx.exe" because it was not found.

Upvotes: 0

ShaunnyBwoy

Reputation: 93

For Windows Services using WCF, I ended the WFC host process and it worked. I hate it when this happens, and it happens randomly at times.

Upvotes: 0

Alexandru

Reputation: 12892

When I faced a similar issue, the only thing that seemed to work was:

Right click the project, going to Settings, and making sure that both Debug and Release builds target the same settings, or have the settings in there that the application tries to load or save.
Deleting the C:\Users(YourUserAccount)\AppData\Local(YourAppName) folder.
Making sure that no files that I had in there were considered "Blocked". Right-clicking my project's included files, I realized that one icon was actually blocked and considered bad because it was downloaded from the internet. I had to click the Unblock button (in example, check this out: http://devierkoeden.com/Images/Articles/Dynamicweb/CustomModules/Part1/BlockedFiles.png - "This file came from another computer and might be blocked to help protect this computer.").

Upvotes: 0

Alan

Reputation: 281

Restart IIS- could be a process attached to the debugger

Upvotes: 3

Eight-Bit Guru

Reputation: 9971

I tried all the other suggestions in the answers here, none of which worked. Eventually I used Process Monitor to discover that my .exe that VS2010 was failing to build was locked by the System process (PID=4). Searching SO for situations involving this yielded this answer.

Summarised: if you have the Application Experience service disabled (as I did) then re-enable and start it. Two years of aggravation ended.

Upvotes: 8

Adrian Booth

Reputation: 154

When I have come across this problem it is to do with the Fact that the project I am trying to build is set as the Startup project in the solution making the .exe in the obj folder locked ( it also appears in your task manager,) right click another project in your solution and choose set startup project. This will release the lock, remove it from task manager and should let you build.

Upvotes: 9

Quinxy von Besiex

Reputation: 976

I also had a problem very similar to this and found the reason in my case was that I had made the bin\debug folder available as a shared folder under VMware and either VMware, Explorer under the VM guest, or maybe even an anti-virus program under the guest (though I don't think I had one installed) was holding a handle to the file(s).

Upvotes: 6

Pedro

Reputation: 2927

I found one simple solution, just disable the Windows Indexing Services for the project folder and subfolders

Upvotes: 14

GregJF

Reputation: 466

Do the simple things first.

Check that part of your solution is not locked by a running process.

For instance, I ran "InstallUtil ' on my windows service(which I normally unit test from a console).

This locked some of my dlls in the bin folder of the windows service project. When I did a rebuild I got the exception in this issue.

I stopped the windows service, rebuilt and it succeeded.

Check Windows Task Manager for your Application, before doing any of the advance steps in this issue.

So when you hear footsteps, think horses not zebras! (from medical student friend)

Upvotes: 1

Chris

Reputation: 28064

I know this is a very old question, but I recently experienced the "cannot copy from obj to bin" error in VS 2012. Every single time I tried to rebuild a certain project, I got the message. The only solution was to do a clean before every rebuild.

After much investigating, it turns out I had an incomplete pragma warning statement in one of my files that did not prevent the compilation from succeeding, but was somehow confusing VS into keeping the file(s) locked.

In my case, I had the following at the top of the file:

#pragma warning(

That's it. I guess I was attempting to do something a while back and got distracted and never finished the process, but the VS warnings about that particular line were lost in the shuffle. Eventually I noticed the warning, removed the line, and rebuild works every time since then.

Upvotes: 0

Ian Mercer

Reputation: 39277

None of the other answers worked for me but closing all open tabs in Visual Studio appears to have solved the problem.

Upvotes: 0

Kevin Shanahan

Reputation: 109

Here's another possibility:

After receiving this error in vs2012 / win7, I went and tried to delete the file in the bin directory and explorer indicated that the file was in use by the XAML UI Designer.

I closed all the tabs I had open in VS, closed VS, then made sure to kill all MSBuild processes in taskmanager. Finally, after restarting VS I was able to build the solution.

and another possible cause:

I have noticed another possible cause for this issue. After doing some code refactoring, moving projects in and out of a solution, my project references were no longer referencing the projects in the solution as expected.

This mislead visual studio to think it could build some projects concurrently, thus creating the file locks.

EDIT: I have had this happen on a few occasions even recently with VS2012 and it does fix it once I set the build order to the correct dependencies, kill any msbuild processes that VS left running, and then restart VS. I kill the msbuild processes just to be sure, but closing VS should kill them off too.

What I usually do to cause this is refactor a project such that it relies on another project within the solution that it wasn't referencing on last build. This sometimes seem to confuse VS and it doesn't update the build order.

To check build order: Right-click the Solution in the Solution Explorer and select "Project Build Order..." and verify that dependencies are properly noted for each project.

Upvotes: 3

Gico

Reputation: 1394

I tried several solutions that you provided, but occasionally I still receive this error. I am positive that my process is not running, and when i try to delete the executable file with internet explorer it is removed from the file list, but then I press F5 and voila, the file is back. It has not been deleted at all.

But if i delete the file through the TotalCommander, the exe file is actually deleted and I can successfully build the project.

I am using windows 7 x64 and total commander 7.56a 32 bit.

Upvotes: 0

Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug

Answers (30)

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