How to Force Delete a Stuck Time Machine Backup in macOS

Why Do Time Machine Backups Get Stuck?

Time Machine is an excellent automated backup solution, but it occasionally encounters issues during the “Preparing backup” phase or while actively transferring data. Network interruptions, corrupt local files, or unexpected disk ejections can cause a backup process to freeze entirely. When this happens, a temporary backup file ending in .inProgress is left on your backup drive. If the system fails to clear this file automatically, it can prevent all future backups from starting, resulting in a persistent “Backup failed” or “Preparing” loop.

Step 1: Stop the Current Backup Process

Before attempting to delete the corrupted file, you must ensure that macOS is not actively trying to write to it.

1. Click the Apple Logo in the top left corner of your screen and select System Settings (or System Preferences on older macOS versions).
2. Navigate to General > Time Machine.
3. If a backup is currently attempting to run, click the small ‘X’ icon next to the progress bar to cancel it. Wait a few moments for the process to fully stop.

Step 2: Locate and Delete the .inProgress File

You must manually delete the corrupted temporary file from your backup drive to clear the bottleneck.

1. Open a new Finder window.
2. In the sidebar, locate your external Time Machine backup drive and click to open it.
3. Open the folder named Backups.backupdb.
4. Inside, open the folder that matches the name of your Mac (e.g., “John’s MacBook Pro”).
5. Scroll to the very bottom of the folder list. Look for a file that ends with the .inProgress extension (it will usually be named with the current date and time).
6. Right-click this .inProgress file and select Move to Trash.
7. You will be prompted to enter your Mac’s administrator password to authorize the deletion.
8. Empty the Trash immediately.

Step 3: Restart and Initiate a New Backup

Once the corrupted file is gone, you need to restart the Time Machine service to establish a clean connection.

1. Restart your Mac (Apple Logo > Restart).
2. Once logged back in, go to System Settings > General > Time Machine.
3. Click Back Up Now to force a fresh backup.

The system will now perform a deep scan of the drive and initiate a clean backup sequence, completely bypassing the previous error loop.