How to Fix It When Time Machine Is Stuck Preparing a Backup

Time Machine has many tricks to ensure error-free backups and backups that take as little time as possible to complete. But in some cases, these two goals can force Time Machine to take a long time preparing for a backup. If you see a very long preparation phase or Time Machine seems to be stuck in the preparation process, this guide should help you fix the problem.

Is Time Machine Stuck in the Preparation Process?

Typically, unless you've made significant changes or added several new files to your drive, the "preparing backup" process is speedy. It's so quick that most Time Machine users never notice it, except for the first Time Machine backup, where the preparation phase takes a long time.

If the preparation process is taking a while, here's how to tell if it's stuck:

1. With Time Machine seemingly stuck in the preparation process, go to the Apple menu and select System Preferences.

2. Select Time Machine.

3. You'll see a Preparing Backup Progress Bar that indicates how far along Time Machine's preparation process is.

4. If the progress bar is moving forward even slowly and incrementally, Time Machine is working. Be patient and don't interrupt the process.

5. If the progress bar doesn't show any movement for more than 30 minutes, Time Machine may be stuck.

   If you've added significant files since the last backup, or if this is your first backup in a while, give the process a few hours or even let it sit overnight.

Cancel the Current Backup Attempt

If the Time Machine backup-preparation process is stuck, you'll need to cancel the current backup attempt before moving on to troubleshooting solutions.

1. To stop Time Machine's current backup preparation process, click the X next to the progress bar.

2. You'll see that Time Machine is stopping the preparation process.

3. When the preparation process has stopped, ensure that Back Up Automatically is unchecked.

4. Next, you'll need to delete the canceled backup process's .inprogress file. Open your Time Machine backup volume and select Backups.backupd.

5. Find the file that ends with .inprogress. Right-click the file and delete it, and then empty the Trash.

How to Fix Time Machine When It's Stuck

After you've canceled the failed backup attempt, try some troubleshooting steps to see if you can get Time Machine to back up your system properly. Two common issues include large files holding up the process and Spotlight Search indexing the backup volume.

Bypass Large Files

Large photo or video files may be hanging up Time Machine. Try excluding them from the backup and see if this solves the problem.

1. In the Time Machine dialog box, select Options.
   

2. Select the plus (+) sign.

3. Navigate to the files or folders you want to exclude and select Exclude. Repeat to exclude more files or folders.

4. Select Save.

5. With large files excluded, try running Time Machine again and see if it still gets stuck on the preparation stage.

Prevent Spotlight From Indexing Time Machine Backup Volume

Spotlight can interfere with the Time Machine preparation process if it's indexing the Time Machine backup volume. Try preventing Spotlight from indexing the Time Machine backup volume by adding it to the Spotlight preference pane Privacy tab. Here's how:

1. Go to the Apple menu and select System Preferences.

2. Select Spotlight.

3. Click the Privacy tab.

4. Select the plus (+) sign and navigate to your Time Machine backup volume, or drag and drop the Time Machine backup volume to the window.

5. Spotlight will no longer index the Time Machine backup volume. Try running your Time Machine backup again and see if this solves the problem.

Additional Troubleshooting Steps to Try

There are a few other fixes to try when Time Machine gets stuck on its preparation process.

1. Restart your Mac. Sometimes a simple restart can solve glitches. Try restarting your Mac and see if this solves Time Machine's issues.

2. Check your network connection. If you're backing up over a network, a weak or non-existent Wi-Fi connection could be causing Time Machine to hang up on its preparation stage. Check your Wi-Fi or internet connection and ensure it's working properly.

3. Check your antivirus settings. Your antivirus solution may be interfering with Time Machine's backup attempt. In your antivirus settings, exclude the Time Machine backup volume.

4. Update your macOS. An outdated macOS version may be causing issues with Time Machine. Update macOS to the latest version and see if this solves the issue.

What Can Corrupt a Time Machine Backup?

Time Machine's file system changelog can become corrupt for various reasons, the most likely being unexpected shutdowns or freezes and removing or turning off external volumes without ejecting them properly first.

When Time Machine determines that the file system changelog isn't usable, it performs a deep scan of the file system to build a new changelog. The deep scan process dramatically extends the time it takes to prepare Time Machine to perform a backup. Luckily, once the deep scan is complete and the changelog is corrected, Time Machine should perform subsequent backups in a usual fashion.

How Does Time Machine Work?

Time Machine uses an inventory system that macOS creates as part of the file system and logs any file that has changed. Time Machine compares this file-change log against its inventory and creates incremental backups. These incremental backups usually don't take much time while ensuring a complete backup of your files.