I received an e-mail this morning from Seth, who was having difficulty getting his initial Time Machine backup completed. Seth graciously agreed to having his question posted here in another edition of Aaron Answers. Below is his question and after the break is my response.

Hi Aaron,

I really appreciate your blog, and wonder if you'd be willing to answer a Time Machine question i've run into. My old backup HD failed, so I bought a new 2T Iomega eGo desktop HD. Partitioned it into 3 partitions, including a 1.1T partition for my time machine backup. All seems to be working fine, except that the backup is too slow to get done unless I leave the computer running for 3-4 days, which I can't do as it's a laptop and I use it all the time. After the first night (8 hours of so) it had only done 20 Gb (out of my 400 Gb). After the second night, it did about 120 Gb. i don't know if I just need to find a 4-day window when I can leave my laptop backing up or if something is wrong with the software. I'm using the new USB2 cord, and it works nice and fast for manually backing up video files etc to other partitions in the drive. The drive seems to work quite fast. If you're able to offer any advice, that would be greatly appreciated!

Thanks, Seth

Time Machine's first backup is a hog

The first time TM backs up your computer it runs slow on average. The slowness isn't because of drive speeds from what I can tell, but rather the amount of data you are backing up. My laptop has about 140 GB of data stored on it. The first time I backed it up it definitely took over night if not quite a bit through the next day. So your 400 GB drive and 3-4 days isn't an estimate that seems too far off the mark. In general (from my experience) once TM gets past the first backup additional backups are incremental and run much, much faster. TM is then only backing up what has changed.

Drive speed and/or connection cables could be an issue

It's possible your connection to your external hard drive isn't as fast as it could be. I'd test it. Use regular USB2 and copy a large (5GB+ if you can) file to the drive. Use a timer or stopwatch and record how long it takes. Next, run the test again with a second USB2 cord (to rule out issues with the first). Finally, if your hard drive supports firewire (IEEE 1394) you should absolutely use it. Especially if it's firewire 800. You may already know this, but there's firewire 400 and 800, and 800 is about the fastest thing on the consumer market right now until USB3 is more prevalent. I do off-site backup with Carbon Copy Cloner to a 250GB external drive via firewire. The first time I did a backup it took one to two hours. That's fast.


You need to get through a full backup. That's the only way to see if you are having longer-term issues with TM or if it's just a matter of the first backup being so burdensome. Second, use the fastest connection your external drive supports. Firewire 800 if possible.

Seth's response:

Thank you so much for your detailed response. I left for the morning, leaving my computer to keep chugging away, and was astonished when I returned that it had completed a backup. I was expecting it to run until late tonight, at the very least. I think that both of your issues you raised were going on, especially the first one (as the USB2 cable I'm using transferred quite quickly with drag-and-drop). I think the backup ended up taking about 11 hours. One the first attempt, though, it ran for about 8 hours and only backed up 20 Gb of data before I cancelled it.

Thanks again.

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This entry was posted by Aaron West on April 29, 2011 at 3:20 PM. It was filed in the following categories: Aaron Answers, Mac. It has been viewed 78823 times and has 24 comments.

24 Responses to Aaron Answers: Time Machine Backups Taking Forever

  1. Brian

    I have about 500gb of data for my first backup. It's been backing up for 3 days and has not even hit 2gb. It says it's going to take over 500 days to complete the initial backup. Do you think that could be my drive or is it normal for it to be so outrageous?

  2. @Brian - 3 days of backing up sounds kind of excessive but it all depends on your drive speed. 500 days is certainly over the top. What kind of hard drive are you using for backups and how is it connected to your computer?

  3. Don

    Just setup my WHS to backup OS X Lion (appears as a Time Machine drive by utilizing a coLinux VM -- http://www.wegotserved.com/2011/10/21/os-lion-appl... ).

    Wanted to confirm I'm seeing similar backup times on the initial backup using Time Machine. Took about 7 min to setup the sparsebundle and mount it. Since then it has taken 13 hours to copy the first 32.9 GB of the entire 228.6 GB, so aprox. 2.54 GB/hour -- that means it could take 90 hours or almost 4 days to complete.

    GB ethernet but the limiting factor is the Mac is only 100MB I believe. The server is an Intel Atom D410 @ 166Ghz, running WHS v1.5. CPU utilization is up and down as expected 0 - 97%, definitely never pegged @ 100%, memory is @ 57% utilization and disk @ 64%. So nothing is saturated .

    On the MacBook 2.1 with 2.16GHz Core 2 Duo CPU is 80-90% idle, about 50% memory, disk peak activity 16.0 MB/sec but watching it only bursts of read activity along with some writes. Similar activity seen on the network side with peaks of 2.9 MB/sec but data send up and down in the 600 KB - 1.2 MB range and data rcvd in the 2 KB - 28 KB range.

    All seems to be running well just that the full backup takes time to collect the data and the overall time depends on the transfer rate to the Time Machine disk. Once I've completed this my MacBook will have to tackle the iMac then I'll be able to see if the i7, Gigabit ehternet and faster drives make any difference.

    Will let you know what my final time ends up being.

  4. fsbox

    I found your blog while I was backing up 400 GB from my Macbook Pro to a new backup disk and, after an entire day, only 60 GB had been backed up.
    I also went to pondini's website... http://pondini.org/TM/D2.html The solution for my problem was very simple: I turned off my antivirus program (Clam Xav). Now time machine is backing up at 80 GB per hour...

  5. Great comment "fsbox," thanks. I'm not too surprised your anti-virus was affecting things but I am surprised by how much. Anti-virus programs tend to cause all sorts of issues during software installs and updates and now I'll add backups to the mix too.

  6. Tom

    After "upgrading" (= fresh install) my Mac Pro (2nd gen) from Mac OS X 10.6.8 to Mac OS X 10.7.5, I am doing an initial TM backup right now (Mac OS X 10.8 is not compatible with this Mac Pro). The estimated time remaining is currently 13 days. The backup size is approximately 1 TB and it has "already" backed up 10 GB (after running for two hours). I am backing up on a perfectly working external FireWire 800 RAID which was blazingly fast for ALL Time Machine backups under 10.6.8. I am once more disappointed by Apple and their newer OS releases. I am running three workstations and with each release (one workstation also runs with OS X 10.8) I am disappointed even more. I miss 10.6.8 on my Mac Pro already, but I am forced to run 10.7 because of different software releases. I will also submit this feedback to Apple.

  7. A few days ago Time Machine began initiating a new back up. Not sure why. I left the machine on two days and a night, and it was still only a quarter done (I have a terrabyte drive iMac). I stopped the backup. When it started again, it started from zero. What a pain! Now it's showing 17 days to complete. This is ridiculous.

  8. @Steve - that sucks to hear. If you look at the history of Time Machine and hardware devices like the Time Capsule there hasn't been many updates over the years. Apple may not be spending much engineering time on these things making them more error prone and more of a headache. It may be time to move on to other solutions.

    I still use Time Machine + a Time Capsule to backup my iMac but I use other tools too like Carbonite and Amazon S3. If I had the cash laying around I'd stop using Apple's solution and buy a Drobo.

  9. George Hotz Sr

    I'm a high school IT man with about 500 MacBookPros. I've been using time machine to back up "image" machines (Lion) every few weeks for over a year and they never took more than 2 hours. Now the same image ( with Apple updates) is still running after 24 hours. I cancel it and try different backup drives, different "Master" units and/or different connectors to no avail. What could have changed so drastically!!

  10. I agree with Tom a few posts above.

    Before 10.7 is was minutes per back up. After hours.. I just bought a bigger drive to expand my back ups to. 436,458 days to go..

    Ran for 8 hrs last night. I think i hit 2.4 gbs out of 200 or so.


  11. Krabbelen

    OK, so it's not just my Mac then? I have installed Lion, too. I hadn't connected my issues with Lion until I read this thread (because I was only doing the incremental backups and also only plugging in my harddrive and backing up sporadically for awhile).

    Now I have a new drive and want to start it from scratch again, and it is telling me 13 days! It will sit there for awhile and not show any progress in the bar, and then every few minutes move a few MB.

    At first I thought I had downloaded something malicious (anyone know if any kind of malware, besides Anti-virus software, can affect backup times)?

  12. Rick Roth

    Same problem, bought a new 1TB drive and connected it directly by ethernet cable to back up and time machine after six tries has not done squat. I turned off everything and made sure it was only backing up and it did 2 gigs out of 176 gigs after two full nights. It said thirty nine days to complete. then another try today for a few hours and it said 379 days to complete. Now it is saying 19 days to complete. This is useless. This is a new macbook pro running lion.

  13. Tim Cullis

    Just bought a 3TB Time Capsule and am now doing my first backup. Rather than going over wireless, I'm using a USB to Ethernet adapter on the MacBook Air and connecting to the Ethernet port on the Time Capsule.

    Time Machine been running 22 minutes so far and backed up 8GB, so I'm expecting the full 191GB to take 7 to 8 hours

  14. badness

    I had snow leopard and I used to backup on a reguiar basis. It took a few hours but nothing as drastic as this using the same back up disk. I think the new OS might be to blame for this issue.

  15. Mac OS is amazing and frustrating. I had to restore from time machine. It is taking forever to backup. When 1 day has passed I get kernel panic and the computer reboots and starts again doing the endless backup. Its already a week been a week and I'm afraid that will never again be able to perform backup

  16. Richard

    Had the same problem, then formated the time machine drive and the total estimated time for 500GB is 7 hours over USB 2 :)

  17. Jeevan

    Thanks to @fsbox for mentioning about the possibility of Anti-Virus software in the delayed backup process. I did shut down the app and the backup speed has skyrocketed.

  18. Hoost

    I do not have any other external drives hooked up to my laptop besides the 3TB external drive I'm trying to do the TM backup to. I'm on my third day of the initial TM backup and the estimated size of the backup has continued to increase even beyond the 500 GB capacity of my laptop's hard drive. How large can a TM backup of a 500 GB drive be? Does it make sense for it be larger? Would multiple accounts cause duplication of system files or something? If this initial backup continues for two more days and the estimated size has increased to something like 800 GB would that be cause for suspicion that it's not doing what it's supposed to?

    Thanks for your help.

  19. Fred Viana

    I managed to fix my problem with backup taking forever... here are things I did.

    Disabled the creation of .DS_Store

    Tuned up the ack delay

    Restarted my Macmini after that and the 3 days backup changed to 45min.

    Made the change on all my 3 Macs and backup has been super fast.

  20. Brandon Williams

    I have just started using Time Machine to back up my Mac Pro. I have 1.1Tb to backup. I also was experiencing the 17 day estimate... and painfully slow progress (410 Gb after 3 days...). I am backing up over my LAN to an older Mac Pro (2006) Running 10.7 Server (10.8 won't run on older machines). I WAS getting only 1 Mb/sec data throughput, according to Activity Monitor.

    I happen to check my Ethernet settings under System Preferences/Network/Ethernet 1/Advanced/Hardware tab... only to discover that my "Speed" was set to 10Mb/sec. So I changed the "Speed" setting to "Automatic" - WOW, my throughput changed instantly to 9.4 Mb/sec and the estimated time is now dropping quickly. If I had done this to begin with, I would be done by now. Yes, it is still slow over Ethernet, but I want a regular network backup via the LAN. I hope this helps someone else.

  21. @Brandon - great comment and feedback. Thank you so much for sharing.

  22. FerBenn

    Same problem.Then, Erased external HD (Lacie USB 3 1TB,porsche design). Deselect all SPOTLIGHT preferences. Open TM preferences start all over again. Now for 111 gb of info. It saids, that it will take 1 hour. Macbook Air 1.7 ghz i5 10.7.5 Lion os. Hope this help someone out there.

  23. Aliminhaas

    Hi everyone,

    I just started backingup my mac book pro with time machine today. It's been 6 hours and TM is stuck at 1.85GB out of 126 gb total. It says remixing time is 44 minutes since the very start and is not progressing. Any suggestions?
    I cannot leave my laptop in my office, I have to take it to home and it will go to sleep during travel. So, I am not sure if TM will be running in the background during this time or will stop due to sleep?

    Thanks for your suggestions!

  24. @Aliminhaas - It's been my experience Time Machine backups take an incredibly long time to finish the first time through. I've personally had them take several days. The only thing I've found that works is to be patient, keep the machine on (no sleeping, no screensaver), and let it do its thing.

    I recognize you have a laptop and this recommendation may not be feasible but it is work has worked for me. I'm not sure what would happen if you put your computer to sleep while the initial backup was running.