@jesterking said in Backup my retropie error?:
That being said, the best... method of backing up the entire SD card that I could find is in this link
At the end of the day, making an sd backup externally really is the best, most all-encompassing method. The same advice is given in the official RetoPie documentation as well.
https://github.com/retropie/retropie-setup/wiki/updating-retropie#making-a-backup-option-1