During post migration tidying I moved all the migrated folders/albums out of the 'migrated catalogue' folder and then deleted the supposedly empty folder.
But then after a while all the moved folders and albums disappeared!! I'm only guessing what has happened but it appears that the deletion of the 'migrated catalogue' was synced before the new location of the folders and albums was synced. The result being that the 'Cloud' then synced back to the desktop thinking that the 'migrated catalogue' together with all the contained folders/albums were to be deleted! It didn't know that I had already moved them out of 'migrated catalogue' on the desktop!
Does this mean that you have to wait till sync has completed before doing any other moving/deleting, just in case. Is this likely to cause problems with anything I do whilst syncing is still going on?
I had the same issue and I'm not sure what to do now. Keeping my historic album structure is what is keeping me in Lightroom. If I have to recreate all of the albums, it may be time to move to another product. Remigrating 88,000+ pictures is an option, but painful.
The issue seems to be the delay in desktop changes being synced with the cloud. There are a few other things that you would normally expect to see happen fairly instantaneously on the desktop, such as adding/changing keywords, but if you do a bunch at the same time it takes a while before you see the changes. Makes me hesitate whilst it catches up which interrupts the workflow.
Re loosing albums. Although it will be hugely frustrating for many, I'm lucky in that I have decided to use them differently so don't need them in their old form. ie I'm trying to use them more as temporary 'collections' whilst sorting for a client or a portfolio project but not as long term organisation. For that I'm trying to make better use of keywords.