Time Machine Slow? Speed it up With This Terminal Hack!

Time machine slow for you? Speed up the initial backup with the following command and run it in a terminal window. To open up terminal just search for it using spotlight and start it.

The terminal window should look something like this:

time machine slow

Speed up time machine backup terminal command:

sudo sysctl debug.lowpri_throttle_enabled=0

Return to default when done (recommended):

sudo sysctl debug.lowpri_throttle_enabled=1

When you enter the commands above you will be asked for your password. It is the same password you use when logging in to your Mac or installing new applications. It won’t show the password when you are typing it.

Also scroll down to read the comments for this post. There are some nice tips from the readers of this site as well!

Time Machine Slow Due to Low Priority Settings

The reason for time machines initial backup being slow is that it defaults to a low priority mode. When you enter the command above it will increase the priority with the cost of using up more resources from your Mac. The benefit here is that the initial backup will go much faster, and I would certainly welcome that over some more power savings.

When you are done, just remember to return to the default mode, if not your machine may feel slow because not only time machine but other background tasks are affected by this command as well.

When the initial backup is done it should be no big issues with the backups after that. In most cases it is the initial backup that makes time machine run slow. Most people just leave it on overnight and it takes care of itself, but if you are in a hurry the suggestions in this article should help.

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Other Suggestions if Backups are taking a long time

Are you backing up via WiFi? That can slow down backups. Make sure you are close to your access point / router or use a physical network cable to connect your Mac directly to the router. Make sure you are connected to a fast 5ghz network.

Format or check the hard drive you are backing up to. Open up disk utility and run a check on your hard drive. Maybe the drive is getting bad, or a repartition and a reformat could help.

If you have cancelled or unexpectedly interrupted the previous backup time machine may take a longer time when making a new backup again.

If you are running antivirus try disabling it during the backup as it may slow it down.

Virtualization apps like Vmware Fusion or Parallels can often write data to your hard drive and this may keep time machine going all the time. Consider excluding virtual machines from your backup.

22 thoughts on “Time Machine Slow? Speed it up With This Terminal Hack!”

  1. This fix was AMAZING! I have a new, 2018 MacBook Pro with 2.6GHz, 6 core processor. The Macbook is directly attached to a LaCie 4big Quadra. Before this fix, it was sooooooo slow to have Time Machine back anything up. I often found myself killing the backup job so I could grab my Macbook and head off to a meeting. What use to take hours, now takes minutes! Thank you so very much for sharing this!

  2. Grrrreat, thanks! Kicked the process from twelve to less than two hours. Is this a solution you can use for, for instance, any update process? Keep up the good work, kind regards from The Netherlands. I’ll share this post in the Apple Netherlands/Belgium support group on Facebook.

    • Leon: Glad it worked! It may be possible to use this command for other background services as well. For example updating icloud photo libraries? I am just guessing here tho. Thank you for sharing the site, it helps. 🙂

  3. hey, thanks for the advice. My throttle setting did go down to 0 from 1 after entering the command, but the backup didn’t get any faster, even though I’m using a brand new Samsung T5 SSD, connected via USB to my Macbook 12″ 2016. Do you have any more advice for me? Thanks!

  4. Did nothing for me where as the original sudo sysctl debug.lowpri_throttle_enabled=0 made back go from 400 kb/sec to 40 MB/sec.

    And that makes sense: if the back up is obeying some throttle flag then changing the priority makes no difference.

  5. I get the same speed out of Time Machine whether I backup to my NAS over Wifi or try to backpu to my external LaCie hard drive. That’s just not right.

  6. what is kind of dumb is Apple could just have a toggle switch on the Time Machine interface to enable or disable this throttle setting (and could revert to off when done).

    Personally, I do first backups when I am not going to be using my computer (eg overnight). Its the perfect time for the throttle. it could even default to this setting for the first time.

    Context: I recently bought a 1 TB SSD to replace my now-useless 2TB time capsule. It had been doing a first backup of 400GB and was on hour 40 and only at about 90%. I googled and found this thread and its cruising along now..


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