If you can't back up or restore your Mac using Time Machine
If Time Machine can’t use your backup disk to back up or restore your files, try these solutions.
How to back up or restore
If you can’t back up or restore
If Time Machine states that your backup disk doesn’t have enough storage space or is nearly full, use a backup disk that has at least twice the storage capacity of your Mac. For example, if your Mac has 1 TB of storage, your backup disk should ideally have at least 2 TB of storage.
Check the connection to your backup disk.
If your backup disk is connected to your Mac, make sure it’s connected directly to your Mac, not through a USB hub or other device.
If your backup disk is connected over your local network, make sure the network connection is good and your Mac is connected to the same network as the backup disk. If you’ve completed a previous network backup successfully, you can verify that backup: press and hold the Option key while choosing Verify Backups from the Time Machine menu in the menu bar.
If you’re also using a cloud-based syncing or backup service, Time Machine may state that some of the files on your Mac cannot be backed up until syncing has been completed. To ensure syncing can be completed promptly, keep your Mac plugged into a power source and connected to the internet. If you don’t want to wait for syncing to be completed, you can exclude your sync folders from the Time Machine backup temporarily.
Check for VPN software or other third-party security software, which can affect the connection to your backup disk.
Make sure the firmware of your backup disk is up to date. Check with the manufacturer of the backup disk for details.
Find out what to do if Time Machine is working but takes a long time to back up.