After upgrading to windows 10 I am unable to back up the catalog. I have changed the permissions to allow full control on my back-up drives and lightroom.exe but I am still receiving the message to check my folder permissions or make sure there is available space. There is plenty of space on the back up hard drives.
Using Windows 10, Lightroom CC. I just tried doing a backup and had no problems. It might be necessary for you to run Lightroom as an administrator. I always run with my administrator account, and have had no issues with Windows 10.
I have already tried running Lightroom as an administrator but it still won't backup.