Lightroom Project corrupted when restoring backup

[bst7]

MacBook Pro 16, M1 Pro

Monterey 12.0.1

Lightroom Classic 11.1

I have a backup of a project with many edits to a few files. The original project (all files, previews, etc) were located in their own Proejct directory in  ~/Lightroom/

(1) When I launch the catalog from the backup disk - it is fine.

(2) When I copy the Project Folder back to ~/Lightroom/ it is fine.

(3) When I copy the Project Folder to a folder in ~/Documents it DOES NOT WORK.

* I get a dialog: "Lightroom encountered an error when reading from its preview cache and needs to quite" - with an "OK" button. I re-launch the catalog - same error.

* I delete JUST the Previews directoy and relaunch. Lightroom rebuilds the Previews, but they are wrong. It looks like any Masks that were applied are corrupted.

So, problem (A) seems to be :

(i) that a backup needs to be restored to the same location (path) in your home directory (perhaps even the user name needs to be the same??) as it was originally.

(ii) The project cannot be copied or moved to another location. 

- launch the project in ~/Lighroom/ it launches fine

- move project to a sub directory in ~/Documents - "cannot read previews"

- move project BACK to ~/Lightroom/ it launches fine

Prolem (B)

If I delete the "Helper" and .lcat-data files in either (1) or (2). It doesn't complain when I relaunch, but the previews are now incomplete and the Masks are corrupted. So, exact same problem.

What are my expectations -

(1) On previous releases of Lightroom, just having the LR-CAT file was sufficient for archival purposes

(2) It didn't matter where you restored a backup too, or copied a project folder too. You may have to "Find Missing Folders", but that was it, it just worked.

This seems very serious to me.

William 

ps

For 2 and 3. This is on a different computer, but the user name (therefore the path) is the same

[bst7]

If I export the Project to the new location, it creates these project files:

.lrcat

.lrcata-data

It rebuilds the Previews, masks, etc just fine.

So, it seems like there is something wrong with the lrcat-data file if this is copied over to a "new location".

[bst7]

Ok - so the problem seems to be:

(1) The Original backup was made from an Intel Mac. Copying that over to an M1 Mac is a problem if copied to ANY OTHER LOCATION than the "original" location (~/Lightroom/ in my case).

[JohanElzenga · Accepted solution]

Check that Lightroom has permissions to read and write to the Documents folder.

[bst7 · Accepted solution]

Wonderful! Thanks, that was it.

Weird, because taking an "exported" catalog and copying that into the same location worked, but copying the Project archive folder directly from the backup did not.

I guess the resolution to this is that if you get this dialog - check your Permissions.

Perhaps Adobe could include that message in this dialog?

Thanks again

William