Information Technology Reference
Delete Files from a Time Machine Backup
When your backup volume gets close to being full, Time Machine
automatically deletes old backups to make space for new ones. It
doesn't warn you about this, by the way, but the first time it happens—
and optionally thereafter—Time Machine does inform you that it has
just deleted some backups, suggesting that you select a different disk
to avoid having more files deleted. (If, instead, you'd like to migrate
your Time Machine backups to a larger volume, read Migrate to a
Larger Time Machine Disk , later.) Be that as it may, these automated
deletions may not occur in the way you expect; I lay out the details in
The Time Machine Schedule Problem , a few pages ahead.
But sometimes you may need to remove files from Time Machine's
backup before they would automatically be deleted. For example:
A large file you've already deleted and will never need again (say,
a gigantic disk image for a software installer) has been backed up—
perhaps multiple times.
You're concerned about sensitive information being stored in a
backup that other people might be able to access.
You decide to exclude a file from Time Machine (see Exclude Files
from Time Machine ) after Time Machine has already backed it up.
Contrary to what the user interface implies, Time Machine doesn't let
you purge just one instance of a particular file from your backups. You
have two choices: delete a single entire snapshot (that is, all the files
from a particular hourly run of Time Machine) or delete all instances
of a single file from a certain location , regardless of how many times
that file was backed up.
Delete an Entire Snapshot
To delete all the files Time Machine backed up during a particular
hourly run, follow these steps:
1. Click the Time Machine Dock icon or choose Enter Time Machine
from the Time Machine
menu to show the “time warp” display.