I recently updated my MacBookPro from Mavericks to Yosemite and found that Time Machine backup speed has really slowed down.

I realized the amount of new/changed files jumped quite a bit after the upgrade, so I expect the first backup to take a while. However, the backup speed seem unusually slow.

I let it run overnight and in 12 hours it copied 18GB out of 500GB, for an effective transfer rate of about 0.025 GB/min. At this rate it will take something like 14 days to complete.

For comparison, and to make sure the external drive and USB ports were basically happy, I copied a 4GB file over to the external drive manually and it measured at 8.5 GB/min (very fast).

Has anyone else seen this and/or have any suggestions for troubleshooting?

My system:

  • MacBookPro, retina, 15-in, late 2013
  • 2.6GHz i7
  • 16 GB RAM
  • 500 GB SSD
  • Seagate Backup Plus Slim portable drives, USB 3.0 (1TB and 2TB)
  • 1
    I have the same problem whether backing up via Thunderbolt or USB. Both are so slow as to not be practical and Thunderbolt makes no difference. This is clearly a software bug.
    – user116935
    Mar 4, 2015 at 18:33
  • @scott I agree - I have switched to Acronis TrueImage and backing it up that way. Kind of a bummer because I liked Time Machine, especially for restoring individual files from back in time.
    – BrianC
    Mar 4, 2015 at 19:25
  • See also apple.stackexchange.com/a/260975/1209
    – rjmunro
    Jan 3, 2020 at 16:05

2 Answers 2


I have a Macbook air late 2013 on Yosemite with similar specs but I have an Apple time capsule instead and the only thing I have found to improve speed is an ethernet cable. Get a connecter from thunderbolt to ethernet and then use an ethernet cable to connect it to the external drive. I haven't really tested this much but it did work the few times I have. Also, your external drive might be getting old. For me it usually takes about an hour or less to do a 90 GB backup. Also check your other computers or devices because if they are backing up, it will slow it down. Hopefully this helps!

  • 1
    In my case I did buy a brand new drive to see if that was the problem (it wasn't). I also did a manual copy of a large file and the speed was decent. (Trying to eliminate hardware issues as the source.)
    – BrianC
    Feb 12, 2015 at 20:34

I had the same problem. My Backup Speed was extremely low and I thought my external HDD is broken, so I tested it the same way as you did and everything was fine.

After that I formatted the HDD and then everything worked fine after that. Downside of that: You loose your old backups.

  • I am not allowed to write a comment, so I had to put my thoughts in the answer field.
    – g_r4ni
    Feb 14, 2018 at 11:27

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