This is for advanced users of version 13.x and above only. If you are not comfortable working with the Windows registry, do no attempt this.
Preparation: Create a backup of your windows registry and a system restore point if possible.
1. Start regedit and Locate: HKLM/Software/DRBackup/DRBackup Imaging/7.0 (Note: If you are on version 13.x, the last folder will be "6.0" instead of 7.0)
2. In the right side along with all the others (such as DefaultPath, etc) create a new string value:
Label = "LogFile"
Value = Full path and filename you want for the log, such as: C:\DR-Svc.log.
3. Restart the DRDiag service, and verify you are getting information into that log.
4. To stop logging you have to remove the registry entry and restart the service again.