Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have an external hard drive connected using USB3 to my macbook pro retina and I am running time machine for the first time. It is going very slow and estimate says "3 days". I don't understand why its taking so long because my hard drive is 335 GB and I would expect a backup to take a few hours tops maybe.

Can anyone explain if this is normal or if i am doing something wrong?

share|improve this question
Do you use Spotlight? – duci9y Nov 24 '12 at 13:31
What do you mean "do you use"? I have never turned on anything specific from what was initially installed – leora Nov 24 '12 at 13:52
The first TM always takes a long time. It might help to turn off Spotlight on the external drive. – patrix Nov 24 '12 at 13:56
How can i turn off Spotlight on the external drive? – leora Nov 24 '12 at 14:02
The first backup takes a long time and the estimate is very unreliable until a significant amount of the work has been done, i.e. do not trust the "3 days". Just let it finish. – Thorbjørn Ravn Andersen Nov 24 '12 at 15:49

This is not normal if every backup takes that long and/or it never finishes.

You should let the backup end if at all possible. Each time you interrupt a backup - you add even more time to check the slow work that was made and then pick up where it left off. If you interrupt a back up too many times, it could take a week to get over a problem spot.

You could:

  • Let it run and see if the next time is quick.
  • Interrupt it and delete the partial backup
  • Clear the backups and start with a clean slate if you don't need the backups or don't care to troubleshoot a temporary issue.

If you want to troubleshoot, you have several options. Apple has a tmdiagnose tool that they use to collect logs and statistics relating to items that can cause problems.

If you can get help from Apple, I would do that and let them provide the training and expertise needed to make sense of the volumes of data that the diagnosis provides.

There are some other things you might try in this article:

Feel free to post back a more specific question if you find the issue doesn't resolve itself or you need more information about how to interpret your results from the article or the diagnosis tool. Also as you commented, it could simply be a bad hardware situation.

share|improve this answer
turns out the external harddrive was a lemon. I tried with a new external harddrive and it worked fine.. initial backup finished in 2 hours – leora Nov 25 '12 at 1:11
Dang - I didn't even address potential hardware failure in my answer. Feel free to edit that in or make a new answer. – bmike Nov 25 '12 at 14:19
up vote 0 down vote accepted

It turns out the external harddrive was a lemon. I tried with a new external hard drive and it worked fine.. initial backup finished in 2 hours and time machines seems to be working fine now.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.