Check that Time Machine is really backing up your Mac
Quick answer
Click the Time Machine icon in the menu bar. The top of the menu shows the date and time of your latest backup.
Why it happens
Time Machine works quietly in the background, so it's easy to lose track. It keeps a record of the last good backup for each backup disk, and shows when the next one is due. If that date is days or weeks old, backups have stopped and it's worth finding out why.
How to fix it
Click the Time Machine icon in the menu bar, the clock with a curved arrow round it. Read the Latest backup line at the top. Today or yesterday means you're in good shape.
No icon? Turn on Time Machine in Menu Bar settings so it's there next time.
Menu Bar›Menu Bar Controls›Time Machine
For more detail, open General, then Time Machine. Each backup disk is listed with its latest backup and when the next one is due.
General›Time Machine
If the last backup is old, plug in your backup drive, then choose Back Up Now from the Time Machine menu. Watch the menu: it shows progress while it runs.
Menu bar›Time Machine›Back Up Now
Checking your latest backup works the same way on macOS 26 and 27. The only label change is the button for adding a disk: Add Backup Disk on 26, Add Backup Disk… on 27.
Still not fixed?
No disk listed in Time Machine settings means backups were never set up, or the disk was removed. Plug in an external drive and click Add Backup Disk. On macOS 27 the button reads Add Backup Disk….
macOS 26 Tahoe General›Time Machine›Add Backup Disk
macOS 27 Golden Gate General›Time Machine›Add Backup Disk…
If the backup fails part way, plug the drive straight into the Mac, not through a hub, and run First Aid on it in Disk Utility.
Disk Utility›First Aid
If it says the disk is full, open Options… and leave out large folders you don't need backed up, or move to a bigger drive.
General›Time Machine›Options…
On a MacBook, backups may pause while you're on battery. Plug in the power adapter, or turn on Back up on battery power in Options….
General›Time Machine›Options…›Back up on battery power
If First Aid reports errors it can't repair, or the drive clicks or keeps disconnecting, the drive itself is failing. That's hardware: replace it, and contact Apple Support or a repair shop if you need help getting files off it.
Questions people ask
How do I know when my last Time Machine backup was?
Click the Time Machine icon in the menu bar. The latest backup's date and time is at the top. You can also see it under General > Time Machine.
How often does Time Machine back up?
Hourly by default, as long as the backup disk is connected. You can change this under Backup Frequency in Time Machine's Options.
Does Time Machine back up when the drive isn't plugged in?
No. Backups only happen while the backup disk is connected or reachable on your network, so plug it in regularly.
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