Cant remove stalled (inProgress) Time Machine backup I have recently switched to a newer MBP from a TM backup. Unfortunately something seems to have gone wrong during the migration. TM cannot complete a backup, it just keep accumulating into a directory, with .inProgress suffix. 

After a bit googling I found this answer, which suggests removing the folder by moving it to the Trash. That doesn't really work as it just says Removing files, but there is literally no progress after hours. I tried to remove the folder from the terminal, that's a no go due to Permission Denied.

I tried to change to a admin account, then do a sudo rm -rf and that results in Operation Not Permitted. Do I need to disable csrutils just to be able to repair a stalled backup?

Suggestions?
tmutil listbackups shows you a list of the backups found on your Time Machine disk.
To delete a backup shown in this list, run

tmutil delete /path/to/backup.inProgress