I have set the APBackup to run an application before it starts archiving. This application goes to a network resource and deletes old files from there before APBackup starts archiving from the same location.
Although this HAS worked before, and I have no clue what made it stop working, I am now getting a security exception from .NET when the application runs (it's a .NET windows form app).
I have specified the username/password in the task details, this is a domain admin username. So as far as I understand, the application will run under that user context. Furthermore, I have changed the APBackup service to run under the same username, but still that exception gets thrown.