Hi,
>”But when I failed to create a key in UpdraftPlus”
Could you elaborate on this? What happened when you tried to create a key?
If the key is not being created then you can move the backups from the source site into the destination sites (your localhost) ‘wp-content/updraft’ folder. Once this is done go to UpdraftPlus’ existing backups page, and click the ‘rescan local storage’ which will then find the backups in the directory, which can then be restored and migrated as usual.
You may also connect to the same remote storage folder e.g. in Dropbox, and then on the existing backups page click the ‘rescan remote storage’ link, which will find these backups, where you can then restore as usual.
Best wishes,
Luke