I am trying to add a post command to a scheduled backup task. If I click the "test command" button it works. But when it gets invoked by the actual backup task it fails. Post Command Syntax: cmd.exe /C UpdateMailBackup.cmd working directory set to the location of the batch file (which is also covered by the system path variable). Error Log Failed to run a child process System error: 267 Execution of user command cmd.exe failed. Error code: 1 Operation has completed with errors. What's in the UpdateMailBackup.cmd file? For troubleshooting purposes, all it does is perform a directory listing on a mapped network drive. I found that if I change the batch file to simply "echo foo" it always works. But when I change it to access a mapped network folder, it only works from the "Test Command" button.