What does error code 3 really mean

I have had a backup fail several times with the following error message:

  • Backup failed with code 3 (Not enough memory)

What does this message really mean?

  • not enough RAM?
    Although I only have 2GB of RAM, the backup has run successfully previously. Additionally, there were no other user applications running in the machine at the time. On top of that, my pagefile is at 3GB and it can if required expand dynamically upto 4GB.

  • not enough disk space?
    The backup files created previously were about 250GB in size. I currently have more than 750GB available on the backup drive.

On the face ot it, I cannot see why the backup should be failing with this message.

It means not enough RAM.
In some cases this might not be the exact cause, a detailed description of the error or the logs would be helpful.


I got this error code (not enough RAM) when COS wasn’t working/connected even though I wasn’t using COS for any backups whatsoever.