Error/moodle/problem deleting old backup temp dirs
From Learnit docs
If your Moodle server is hosted on a Windows Server running IIS/WinCache this error may be occurring due to a bug with WinCache - see MDL-35066 for more information on this.
If your Moodle server is hosted on a Windows Server running IIS/WinCache this error may be occurring due to a bug with WinCache - see MDL-35066 for more information on this.