How to Use a Time Machine Drive for Both File Storage and Backups

mac external drive

When you set up Time Machine, your Mac wants to use an entire external drive exclusively for backups. Here’s how you can get around that and use a Time Machine drive both for backups and file storage.

Using a 2 TB external drive for Time Machine backups of a Mac with a 128 GB solid-state drive doesn’t make much sense. Better to put that external drive to use storing video files and other data you might need.

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The Quick and Dirty Method

The easiest way to store files on your Time Machine drive is just placing the files on there directly. Plug in your Time Machine drive and open it in the Finder. You’ll see a folder named “Backups.backupdb”. Time Machine stores all its backup files under this folder. Just leave this folder alone and let Time Machine use it normally.

Place personal files and folders outside the Backups.backupdb folder. Don’t place anything inside the Backups.backupdb folder — Time Machine automatically deletes files and folders inside there to free up space, so you may find your personal files deleted if put them there.

Bear in mind that Time Machine requires the drive be formatted with the Mac’s HFS+ file system, which means you won’t be able to easily access these files on Windows PCs or anything else that isn’t a Mac. Time Machine will also work toward filling up the entire drive, not leaving extra room for your files.

Create Separate Partitions for Backups and Files

The ideal way to do this is to create separate partitions on the external drive. Use one for Time Machine backups and another for your personal files. This will ensure your Time Machine backups don’t grow too large, so you’ll always have room for your personal files. You can also make the files partition an ExFAT partition, which means you can use it with Windows PCs and practically any other device you can connect an external drive to.

You’ll need to use the Disk Utility built into your Mac to work with partitions. Press Command + Space, type Disk Utility, and press Enter to open it.

In the Disk Utility window, select the drive you’re using for Time Machine backups and click the Partition heading.

If you’ve already set up the drive to work with time machine, drag the handle at the bottom of the time machine partition to shrink the partition and then click Apply. This will keep your existing Time Machine backups.

Afterwards, you can click the + button and create a new partition just for file storage. Choose the ExFAT file system for it for maximum compatibility with other operating systems and devices.

Give the new partition a meaningful name — like “Files” — to keep track of which is which.

If you’re setting up the drive from scratch or don’t mind wiping your Time Machine backups and starting over from scratch, you can also do that. Click the “Partition Layout” option and choose “2 Partitions.” Give each partition a meaningful name, choosing Mac OS Extended (Case-sensitive) for the Time Machine partition and ExFAT for the file storage partition.

This process will wipe all the files on the drive! You’ll have to start using Time Machine from scratch, so you’ll lose any old backups and personal files that may be stored anywhere on the drive.

If you resized an existing Time Machine partition, Time Machine should automatically keep using it to back up to. If you wiped your drive or you’re setting up Time Machine from scratch, you’ll need to point it at that specific partition. Choose the Backups partition in Time Machine’s settings and Time Machine will back up to that specific partition only, not the entire drive.

Every time you connect your drive to your computer, you’ll see two different volumes. These are the two partitions on the drive. You can save files to the files partition, leaving the backups partition for Time Machine alone. Bear in mind that the drive may be slow if you’re reading and writing files while Time Machine is backing up to it.


Files you store on the external drive won’t be backed up by Time Machine, so bear that in mind. If the files are important, you’ll want to have redundant backups. On the other hand, if they’re just videos and other types of data you could download again from the Internet, there’s no need to have multiple redundant copies. You can always just download them again if your drive fails.

Image Credit: Karen on Flickr

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.