Lightroom Classic will no longer back up catalog

[OnTheRoad41]

For no discernable reason (at least to me) Lightroom Classic (updated as of yesterday) will no longer back up the catalog. I have tried several different drives both external and internal, won't back up. It tells me "Lightroom was unable to back up the catalogue named "Pam Photos 2023". 
Please check your folder permissions, and make sure you have available space on your backup drive and main catalogue's drive."

My F: drive has over 1.2Tb of space. My D: drive has 300+MB of space. LR will not back up to either. I have rebooted, tried backing up at least a dozen times. I get the same backup error every time. 

I'm using Win11 v23H2, OS build 22731.2199, 64.0 GB (63.7 GB usable),12th Gen Intel(R) Core(TM) i7-12700 2.10 GHz, 64-bit operating system, x64-based processor.

To the best of my recollection, I haven't changed anything about my computer or LR, it just seemed to stop backing up (I have it set to backup every time it exits).

In the attached system info "Lightroom Specs" it says it's using Win10 but I am using Win 11. I have no idea why.

[Lauca]

Are you sure LrC is trying to backup on drive F: ? Could you double check the complet path in the closing window where you have the Backup button ?

[JohanElzenga]

"My F: drive has over 1.2Tb of space. My D: drive has 300+MB of space."

Where is your Lightroom catalog stored? As the error message says, you need enough space on both the destination drive for the backup as well as on the drive where your catalog is located. If the latter is your D: drive and you really have 300+MB (not GB) free space on that drive, then that explains it. 300MB is nothing at all.

[OnTheRoad41]

Sorry, mis-wrote, it has 300+GB (of 2TB). 

[OnTheRoad41]

Again for no discernable reason, after I created a new catalog I went back to my original catalog and tried and SUCCEEDED in backing it up and now it backs up consistently. As far as I know, I did nothing other than close the catalog (after it unsuccessfully tried to back up), create a new catalog and succeed in backing it up, then open the original catalog and now it works.

[JohanElzenga]

Don't you love problems that solve themselves?  🙂

[OnTheRoad41]

All I REALLY care about is that it works!