Spotlight Keeps Indexing Backup Drive #
It may be that Time Machine can’t proceed or complete a backup due to a Spotlight indexing error. During this period, take a look at the Spotlight icon in the upper right corner of your screen. Is there a tiny dot pulsating in the center of the spyglass? Click on the icon. Is there a progress bar displayed? Generally, Spotlight indexing is a good thing. If it has only been a couple of hours then let the process continue.
However, at times it may hang and never progress after many hours, preventing further backups from taking place.
Go to System Prefs –> Spotlight –> Privacy Tab.
Drag your Time Machine disk into the window. It should now be among the items to exclude from indexing.
Now quit System Prefs.
Reboot your Mac.
Reopen System Prefs and remove (“-“) the Time Machine disk from the window.
Now initiate a backup.
This should clear out Spotlights cache. Naturally, Spotlight should begin indexing again (maybe even for a few hours depending on how much data there is), but it should eventually stop.