[01:08:14][CopyPipelineFiles] Copying bin\QAAWS\*****.dll to obj\QAAWS\Package\PackageTmp\bin\*****.dll.
[01:08:14][CopyPipelineFiles] C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v11.0\Web\Microsoft.Web.Publishing.targets(2583, 5): Copying file bin\QAAWS\*****.dll to obj\QAAWS\Package\PackageTmp\bin\*****.dll failed. The requested operation cannot be performed on a file with a user-mapped section open.
it seemed the problem happened all in a sudden, the build failed at copying files to output folder, and it failed on different files for each build, so seemed it's not problem with the file itself. I disabled anti-virus software, but no luck. I checked the *****.dll in ProcessExplore, tried to figure out whether there is any other program using that DLL, but no clue found. Since those files are actually in TeamCity/BuildAgent folder, I don't really think it's been used by any other program, seemed it's been locked by TeamCity itself. TeamCity version is 8.1.5. DB is MSSQL. Any suggestion?