Photoshop Elements 2020 - backups

Trying to do an incremental backup (Already have a full  backup)Did not have to reconnect missing files (had None) .  Select Destination drive :os (c).  Then backup path c:\

Previous Backup:  c:\photoshop job\backup .  The hit save backup.    Working fine until I get his error code:

Error encountered while writing Files  c\Program Data\adobe\Elements organizer\catalog\Job\catalog.pse 18db.  Tried repair and then optimized catalog. That worked fine.  One article said to convert it but this catalog was made with the new elements program.  When I did try to convert it a dialog box opens to choose the file to convert from and there wasnt any there.  I can browse it but what do I convert it from.

So if you have any ideas as to what is going on  I would appreciate any help,  Thank you

By @mec4cast

So, you create your backup on your original C drive? What happens if your computer is stolen or crashes? The general rule is to store backups on different external drives.

A backup from the organizer is a folder. Same for an incremental backup. Exactly the same folder structure, with the same components: catalog.buc, backup.tly and renamed photo files and components.

So you end up with the full backup folder and as many other folders as you have incremental backups. You'll need all of them when you restore. So name each folder with a descriptive name to be able to get to them when you are asked in the restore process. Logically, store those backups on the same external drive.

Even if the backup ends well, be sure to test the restore process. Very frequent problems when you are not used to it. You'll discover that you may not save much backup time or disk space. So the bottom line is probably to avoid totally incremental backups.

Where does the incremental backup(s) reside in the directory structure? Should it be at the same level as the Full Backup or is it a separate or sub-directory? Burning desire to know this answer.