Command copy exited with code 4 when building - Visual Studio restart solves it

Question

Every now and then when I build my solution here  with 7 projects in it  I get the dreaded  Command copy exited with code 4  error  in Visual Studio 2010 Premium ed   This is because of the post-build event not being able to go through   Here s what solves the problem  temporarily   Sometimes  A restart of Visual Studio and I m able to build the solution Sometimes   Both a restart of Visual Studio and my file manager of choice  Q-Dir 4 37  solves it    Here s what the post-build event looks like   xcopy    SolutionDir Solution Items References   dll     TargetDir    Y   When you get the command copy exited with code  insert value  error  it s normally because of the following    read   write permissions missing files wrong directories   However - obviously at times when I build the solution  there s no problem   FYI  I uninstalled ReSharper 5 1 1 two weeks ago and Visual Studio s been giving me some errors since then  among them not being able to debug   I re-installed Visual Studio and it s working better since then  but still get this problem  Could it have to do with some ReSharper stuff being somewhere   Have you had the same problem and solved it  Or do you have any possible solution to it

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While  C may ignore errors  it might not be the real solution as there could be files that MUST be copied in order for the build to be successful   The most common issue is the missing quotes around the pre-defined command tags  such as  TargetDir   When one creates various branches and paths in code or TFS  there is a very high chance for this to occur   Sometimes if the file is read only  it will cause issues too  Add the  R option to allow read only files to be copied over  You can find list of available options at   http   www microsoft com resources documentation windows xp all proddocs en-us xcopy mspx mfr true  Another possible issue is that the underlying folder cannot be accessed  If so  trying performing  start xcopy  instead of  xcopy   This will open another command window but with admin priveleges

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In case the post build event contains copy xcopy command for copying build output to some directory which usually is the most common post build operation  the problem can occur in case the full directory path either of source or target destinations contain folder names which include spaces  Remove space for the directory name s  and try

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I have also faced this problem Double check the result in the error window    In my case  a tailing   was crashing xcopy  as I was using   TargetDir    In my case   SolutionDir    bin  If you re using any other output  this needs to be adjusted   Also note that start xcopy does not fix it  if the error is gone after compiling  It might have just been suppressed by the command line and no file has actually been copied   You can btw manually execute your xcopy commands in a command shell  You will get more details when executing them there  pointing you in the right direction

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In my case my   OutDir  was simply       Build  i e  some relative path  And  when I was trying to xcopy as follows xcopy  y    OutDir Proj1 dll   Anypath anyfolder   I was getting the exit code error 4   What s happening was  this command was getting executed in the   OutDir   in my case build folder  itself and not the directory where the csproj file of the project was located  as we would normally expect   Hence  I kept getting File not found error  corresponding to exit code 4    I couldn t figure this out until I wrote cd in the Post Build events  to print which directory this was getting executed in   So  to summarize  if we re wishing to copy   xcopy files from the   OutDir   either use    TargetDir    which is complete path for output directory  or need not specify any path at all

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If you are running Windows 7 onward  you can try the new  robocopy  command   robocopy    SolutionDir Solution Items References   dll     TargetDir     More information about robocopy can be found here

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To expand on rhughes answer   The robocopy works beautifully  just incase you need to include sub directories you can use  e to include subs and copy empty directories or  s to include subs excluding empty directories   Also robocopy will report back a few things like if new files were copied  this will cause VS to complain since anything above 0 is a failure and robocopy will return 1 if new files have been found  Its worth to mention that robocopy first compares the Source Dest and only copies the updated new files   To get around this use    robocopy    SolutionDir Solution Items References   dll     TargetDir      amp  IF  ERRORLEVEL  LEQ 4 exit  B 0

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I got this error because the user account that TFS Build Service was running under did not have permissions to write to the destination folder  Right-click on the folder-- gt Properties-- gt Security

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I got this error because of the file was opened in another instance   when i closed the file and again re-build the solution  it was successfully copied

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I am getting something similar using an xcopy with the  exclude option  In my case  I found that editing the post-build event  something harmless like a newline after the command  and saving the project causes the error to happen  Re-saving the file specified in the  exclude option causes it to work again

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I ve invariably found this to be a file locking issue  Code 4 is Cannot Access File  One partial solution I found is to use the  C option for xcopy  which continues on error   Not really a solution but mostly it has stopped my builds from failing   Another solution which only works on 32 bit is to use the unlocker tool to release the windows handles on the file before the copy     Edit  I ve just realised that it works under 64 bits too

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I faced same issue  I deleted post-build events and it started working  Some times when we add some SQL components it may add post build commands also

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As mentioned in many sites  there are various reasons for this  For me it was due to the length of Source and Destination  Path length   I tried xcopy in the command prompt and I was unable to type the complete source and path  after some characters it wont allow you to type   I then reduced the path length and was able to run  Hope this helps

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I had the same error with xcopy in connection with the Test Engine  I am using VisualStudio Professional 2013  By default Test -  Test Settings -  Keep Test Execution Engine Running seems to be the reason for my error code 4 with xcopy  Switching it off solved the problem  The execution engine seems to keep hold on some  dlls

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Can be caused by VMWare Workstation with Shared Folders  I have the problem always when the destinatinon folder of the xcopy is also mapped as Shared Folder in a VM   I solved it with a script running in the vm and deleting the content of the shared folder

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Error code 4 can mean a lot of things  so I recommend reading the other answers as well until you find a solution that works for you AND you understand WHY it works  some solutions only disable error handling  which may only mask the problem but not solve it    This can be a file locking issue related to parallel building  A workaround is to not use parallel building  This is the default behavior  but if you are using the -m option  then projects will be built in parallel  The following variations should not build projects in parallel  so you will not run into the file locking problem   msbuild -m 1 msbuild -maxcpucount 1 msbuild   Note that  contrary to what has been said here  this even happens with the  latest  version of MSBuild  from Build Tools for Visual Studio 2019    The best solution is probably to make sure you don t need to copy files in a post-build step  In some situations  you can also disable post-build steps when building with MSBuild on a build server  https   stackoverflow com a 55899347 2279059

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I faced the same issue in case of XCOPY after build is done  In my case the issue was happening because of READ-ONLY permissions set on folders   I added attrib -R command before XCOPY and it solved the issue   Hope it helps someone

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Run VS in Administrator mode and it should work fine

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This can happen in multiple cases    When the complete string path is longer than 254 chars  When the name of the file to be copied is wrong  When the target path is wrong  When the readonly attribute is set on the copied file or target folder

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I had the same problem  A simple  Clean Solution  in VS cleared the error  but it was a temporary solution

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I had the same issue  It was caused by having the same flag twice  for example   if   ConfigurationName     Release  xcopy    TargetDir       SolutionDir Deployment   ProjectName      e  d  i  y  e   Observe that the   e  flag appears twice  Removing the duplicate solved the issue

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I don t see anything in here to suggest that this is a web-app but I have experienced this issue myself - I ve got two xcopy commands on a post-build event and only one of them was failing   Something had a lock on the file  and it wasn t Visual Studio  as I tried restarting it    The only other thing that would have used the dll I built was IIS   And lo and behold   A simple iisreset did the trick for me

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I crossed the same error  but it is not due to the file is locked  but the file is missing   The reason why VS tried to copy an not existing file  is because of the Post-build event command   After I cleared that  problem solved   UPDATE   As  rhughes commented      The real issue is how to get the command here to work  rather than to   remove it    and he is absolutely right

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If you are here because your project fails to build on a build server  but builds fine  manually  on a dev machine  and you are doing xcopy only for debugging and to emulate a production environment on a dev machine  then you may want to look at this solution   https   stackoverflow com a 1732478 2279059  You simply turn off post build events on the build server using  msbuild foo sln  p PostBuildEvent    This is not good enough if you have other post build events that also need to run on the build server  and it is not a general solution  However  since there are so many different causes of this problem  there cannot be a general solution  One of the many answers to this question  and its duplicates  will probably help  but be careful with approaches that only somehow circumvent error handling  such as xcopy  C   Those may work for you  particularly also in the build server scenario  but I think this one is more reliable  IF it can be used   It has also been suggested that with newer versions of Visual Studio  the problem no longer exists  so if you are using an old version  consider updating your build tools

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I found that setting the file s Copy To Output Directory parameter to Copy Always seems to have cleared up the locking issue   Although now I have 2 copies of the files and need to delete one

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I had the same problem  However  nothing worked for me  I solved the issue by adding  exit 0   to my code  The problem was that while I was doing copying of the files  sometimes the last file could not be found  and the bat returned a non-zero value   Hope this helps someone

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What fixed it for me   dig down to the specific solution for the project you want i e NOT the overall solution file for all the projects   Do try - I tried everything else mentioned here but to no avail

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As I am writing a DLL library I used the xcopy command to copy the library where the program can find and load it  After several times of opening and closing the program there was still an open process of it in taskmanager which i did not recognized    Look for any process from which the file may be used and close it

[visual-studio] Command copy exited with code 4 when building - Visual Studio restart solves it

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