Hi.

Am using periodic backup plugin to do full backup of our Jenkins installation on Windows. The symlink files (lastBuild, last SucessfulBuild, last FailedBuild etc), get saved as directories in the backup .zip file, and restored that way. These directories then cause errors in subsequent builds as Jenkins goes to update the symlinks and can't since they are directories.

ln builds\lastSuccessfulBuild C:\Users\build_user\.jenkins\jobs\Disk_Monitor\lastSuccessful failed
hudson.util.jna.WinIOException: Failed to create a symlink C:\Users\build_user\.jenkins\jobs\Disk_Monitor\lastSuccessful to builds\lastSuccessfulBuild error=183:Cannot create a file when that file already exists
at hudson.util.jna.Kernel32Utils.createSymbolicLink(Kernel32Utils.java:93)
at hudson.Util.createSymlink(Util.java:1132)
at hudson.model.Run.createSymlink(Run.java:1865)
at hudson.model.Run.updateSymlinks(Run.java:1846)
at hudson.model.Run.execute(Run.java:1757)
at hudson.matrix.MatrixBuild.run(MatrixBuild.java:306)
at hudson.model.ResourceController.execute(ResourceController.java:89)
at hudson.model.Executor.run(Executor.java:240)
at hudson.model.OneOffExecutor.run(OneOffExecutor.java:43)

The plugin should try to save these symlinks and restore them properly.

Related: JENKINS-18924. https://issues.jenkins-ci.org/browse/JENKINS-18924