the first time I migrate my classic CC lib to CC I had a bunch of Pics missing. So I deleted the import and all the Pics (about 6000), got back to classic CC to fix all the missing Pics and tried to migrate again. That doesn't work - as said in the desciption - it only works once. So I tried to rename the catalog, changed it with classic CC again, deinstalled Lightroom CC with deleting the presets and than reinstalled CC. Nothing helped. Somewhere deep in my mac there must be a file that let CC remember ... Does someone have an idea?
I would like help with this as well
If you delete your cloud library entirely via the web app (Go to Accounts and you'll see a button to "Delete Lightroom Library") you can then re-start the migrate. I did this repeatedly before I finally got all 25000 photos migrated. Bear in mind that deleting the lightroom library in the cloud deletes all your photos, albums, etc. You are effectively wiping the slate clean and starting again.