Hi,
I just resolved this issue, for me at least.
So after reading this and all other top referrals on google, following the advice sans success I dropped it as a lost cause, until, while I was browsing files in finder saw that one had a cloud on it, but of and on, and if I went into that folder the subfolders would go: cloud then no cloud then updating the n no cloud, etc.
Something was clearly fishy here. I tried to access the files via browser and only got as far as the main folder. Going back it seemed that the files had gotten stuck in "limbo" somehow and that the solution might be to delete them.
Not possible said the cheeky computer to the tired person, the files would just be deleting forever without reaching the trashcan. Then I shut off the wifi, held both thumbs and tried deleting the files, and voila they where gone!
Wifi on, confirmed online, gone. (sadly actually but hey, would rather have lost files but not lost computer)
Bird process continued for a minute or so until it settled down together with my aching stomach and the computer fan.
Cheers!