I have noticed that copy only backups does not allow for differential backups. What is the reason the copy-only backup option is disabled for differential backups?
It can be specified in TSQL but the documentation states
COPY_ONLYhas no effect when specified with the
There's no need for copy only differential backups because you can just take a normal differential backup.
Taking a differential backup doesn't break anything as each such backup is cumulative and contains all changes since the last full backup.
If you were to take a full backup without
copy_only that would potentially be problematic as it resets the differential base (clears the bitmaps containing information about which extents have changed).