Fix Time Machine When Stuck on “Preparing Backup” in Mac OS X
Time Machine is by far the simplest way to keep regular and reliable backups of a Mac, and usually the automatic backups start and finish without any incident. On some rare occasions though, Time Machine may get stuck* on the “Preparing Backup” stage for an inordinately long amount of time, causing a backup to never start, let alone finish. It’s these failed backup attempts that we’re looking to remedy here.
We should point out that if you haven’t backed up a Mac in a while, say a few months, it’s normal for the “Preparing Backup” stage of Time Machine to take a while to gather data before beginning, particularly if you have a large drive to backup. What’s not normal is for the Preparing Backup stage to take 12-24 hours, getting stuck in that stage overnight or all day long, for example (unless perhaps you have some truly absurd amount of disk space, then it may take that long and be normal).















