I have an external disk that should be unmounted (NOT ejected) except for a short time each day to run a CCC backup. Unfortunately, CCC often fails to unmount the disk, and my manual unmounting script fails with this message:

Volume 2propstore on disk8 failed to unmount: dissented by PID 3270 (/System/Library/PrivateFrameworks/PhotoLibraryServices.framework/Versions/A/Support/photolibraryd)

It’s a pain to have to deal with this, sometimes several times each day. The only way to unmount the disk is to find the PID of photolibraryd and manually kill it.

Searches on photolibraryd seem to say that it’s analyzing and indexing my photos for iCloud Photo Library and photo streaming. All iCloud services are turned off in Internet Accounts and I’ve never used photo streaming (I don’t ever even use Photos).

Why is Apple running tasks that are poking around in my external disk in the first place, to index photos for a service (iCloud) that I have specifically disabled? In addition to annoyingly preventing me from manipulating my disks the way I want, it seems creepy and intrusive.

Any thoughts as to how I can modify this behavior?

Open iCloud in System Preferences and make sure that Photos is not set to sync.

Open and see if there is a “System Library” defined.

Thanks for the ideas, @tjluoma!

Everything iCloud is turned off in System Preferences.

I don’t use Photos, so I’m not sure I know what you mean. The only thing I find that looks likely is there’s a “Library Location:” file path in Photos>Preferences>General. Under that are two buttons: “Show in Finder” and “Use as System Photo Library”. The latter button is greyed out.

(6teen is the MBP’s internal drive.)

I suppose that you mean an external HFS+ or APFS volume that should be unmounted – which is not different from ejecting it. The underlying physical drive is not ejected by this and the volume may be remounted using Disk Utility, diskutil (in terminal), or by Carbon Copy Cloner itself when starting a task.

I typically manually force-eject a volume using the Finder or Command-e when this happens since, in my usage, the problem is rare. You should not have to kill a dissenting application to eject/dismount a volume.

What macOS version, CCC version version, and scripting language are you using? Are you triggering your script from CCC using task advanced settings? It is difficult to diagnose what is happening without more information.

If you are running up-to-date software versions, the absolute best source for help is use of “Ask a question” from CCC’s Help menu. Bombich is fantastically helpful.