Visual Studio locks output file on build

Question

I have a simple WinForms solution in VS 2010. Whenever I build it, output file (bin\\debug\\app.exe) ends up locked, and subsequent builds fail with a message like \"

Answer 1

Base on the great Stormenet answer, I put up a small script that should work in all cases.

Here is the code to put in the pre build event text box

$(SolutionDir)\BuildProcess\PreBuildEvents.bat  "$(TargetPath)"  "$(TargetFileName)"  "$(TargetDir)"  "$(TargetName)"

Here is the script to copy in the file $(SolutionDir)\BuildProcess\PreBuildEvents.bat (of course you can modify this path):

REM This script is invoked before compiling an assembly, and if the target file exist, it moves it to a temporary location
REM The file-move works even if the existing assembly file is currently locked-by/in-use-in any process.
REM This way we can be sure that the compilation won't end up claiming the assembly cannot be erased!

echo PreBuildEvents 
echo  $(TargetPath) is %1
echo  $(TargetFileName) is %2 
echo  $(TargetDir) is %3   
echo  $(TargetName) is %4

set dir=C:\temp\LockedAssemblies

if not exist %dir% (mkdir %dir%)

REM delete all assemblies moved not really locked by a process
del "%dir%\*" /q

REM assembly file (.exe / .dll) - .pdb file - eventually .xml file (documentation) are concerned
REM use %random% to let coexists several process that hold several versions of locked assemblies
if exist "%1"  move "%1" "%dir%\%2.locked.%random%"
if exist "%3%4.pdb" move "%3%4.pdb" "%dir%\%4.pdb.locked%random%"
if exist "%3%4.xml.locked" del "%dir%\%4.xml.locked%random%"

REM Code with Macros
REM   if exist "$(TargetPath)"  move "$(TargetPath)" "C:\temp\LockedAssemblies\$(TargetFileName).locked.%random%"
REM   if exist "$(TargetDir)$(TargetName).pdb" move "C:\temp\LockedAssemblies\$(TargetName).pdb" "$(TargetDir)$(TargetName).pdb.locked%random%"
REM   if exist "$(TargetDir)$(TargetName).xml.locked" del "C:\temp\LockedAssemblies\$(TargetName).xml.locked%random%"