[Updated December 18, 2014]
Time Machine for OS X was first introduced all the way back in 2004 in OS X Leopard. Since then it’s become the best way to back up your Mac.
This doesn’t mean that Time Machine is perfect, far from it. There are some issues that can come up from time to time, most notably the “Preparing Backup” issue that seemingly locks up your Time Machine backups. If your Time Machine gets stuck on this step for more than 10 minutes when you backup regularly, something’s probably wrong.
Fear not, as there’s a fix for this that should get you backing up again in no time.
If you notice your Time Machine drive running for far more time than you think a regular backup should take, open up Time Machine preferences (System Preferences > Time Machine.
If something is wrong you’ll probably see this screen saying Preparing backup… If that’s the case follow the steps below.
The first step is to click the X button next to the progress bar to cancel the current backup. This can be found in the Time Machine preferences window we just looked at.
You’ll know the backup stopped when the progress bar goes away and Preparing backup… disappears. Now that you’ve stopped the bad backup it’s time to fix the issue.
Remove inProgress File
Open up a Finder window and navigate to your Time Machine drive. There, find the Backups.backupd folder and open it up.
Here, you’ll see a list of all your most recent backups. There should be a file here that ends in .inProgress.
Select this inProgress file and delete it. The file should only be about 3-5kb, so you’re not deleting a backup file, but instead a progress and change log of sorts. With the file gone you can finish up.
Click on the Apple logo in the upper left corner of your Menu Bar and choose Restart. Make sure your Time Machine drive is connected while the restart is happening.
Deleting this file and restarting with the Time Machine drive attached should force Spotlight to reindex the drive. This reindex should fix your hanging issues when trying to do a backup.
When Spotlight is done working its magic, there’s one last step.
Start a New Backup Manually
Your Time Machine probably runs every hour, which means you’ll have to wait to see if it worked, right? Not really. You can initiate a backup manually by clicking on the Time Machine icon in the Menu Bar and choosing Back Up Now.
Time Machine will still give you the Preparing backup… message but this time it should only last at most 5 minutes. IF you were successful you should see your backup start.
If you continue to have issues with Time Machine you may want to run Disk Utility on it to fix any drive issues.
Update: Some of the things that can cause a Time Machine back-up to stop functioning include the following:
- The Time Machine drive was disconnected while it was performing a back-up. Any time you disconnect a drive, be sure to check the status of Time Machine first.
- The external drive was unplugged from the computer without being ejected properly. Always eject all drives before unplugging them from the USB port.
- The Mac was forced to restart while Time Machine was performing a back-up. Try to avoid this if possible.
- A software update was installed while the back-up was taking place. Some updates overwrite important files, and if they are doing so while the back-up is happening, it cause the back-up files to become corrupt.
Try to avoid any of these incidences from occurring by always checking the status of Time Machine before shutting down or restarting. Doing so can avoid a lot of problem for the back-up system.