Time Capsule creates a challenge

I was thinking something was not right with my wife's MacBook. It wasn't because she was complaining about anything; to the contrary over the last week she didn't say anything about the machine. It was quiet. Too quiet.

Last night while I was sitting down watching TV with Allison she finally let it out:

"That new Mac is really slow. My Windows machine was faster."

Wonderful I said to myself, let me see what's up. I grabbed her white MacBook and saw by the dock bar that she didn't have anything running so I started up Firefox. Sure enough, there was a very long delay before the application window appeared.

"See?" she said "It's really slow! It's not just me!"

Apparently I have some deep technical gift, an ability to approach any technology problem in the house and by simply laying hands on the offending device the problem is immediately solved without me doing anything. At least, that's the way Allison sees it and it's just one of the reasons she's kept me around for so many years. My gift had apparently left me.

I quickly scanned around the desktop of the MacBook and noticed that the Time Machine icon was happily spinning away. When I clicked on the icon I saw the little "Preparing Backup..." message. Over the course of the next 10 minutes or so I noticed that it kept spinning and as a result loading up applications was very slow. I tried to kill the process but it would simply not pay attention to me.

I ended up doing a restart on the machine, which took a while by itself. Once OS X restarted and I was back at the desktop I stopped Time Machine and tried loading up applications. Sure enough, everything was nice and fast again.

It turns out Allison's MacBook was having trouble connecting to our Time Capsule. I went through everything I could, including using the AirPort Utility to attach to the TC, checking all the settings and everything seemed to be fine. Multiple consecutive attempts to restart Time Machine and let it run simply resulted in more waiting while "Preparing Backup..." was spinning away in the background. This led to multiple forced shutdowns while trying different settings.

Finally I started to get some error messages:

Which was quickly followed by:

This last one was interesting because clicking the Initialize... button resulted in Disk Utility loading up, which couldn't see the Time Capsule drive.

I decided to start over with the Time Capsule since I had another backup of all of Allison's files. I used the AirPort Utility to erase the Time Capsule drive and start over, then made sure I ejected the Time Capsule in the Finder. I did this because in my scans of various forums I had read that Time Capsule seemed sensitive to drives that were already mounted; it was better to let Time Machine mount the drive as it needed it for backups.

Once I did all of this I started up Time Machine, chose the drive and let it start out as a new backup. Since it had to backup the entire machine it took most of last night and on close inspection this morning the hourly backups were now working properly and the performance was back to normal.

The lesson I learned from all of this is that though I love the work Apple has done with their products, especially making them easy to use for most everything, there is still work to be done. This did not appear to be a configuration problem because I initially had Time Machine and our Time Capsule working just fine; it just suddenly decided to stop working properly, something that my reading last night indicates is a fairly common occurrence.

It also means that I now have to check on Allison's MacBook more regularly to ensure that the backups are happening properly. Given the plethora of Time Machine error messages my other Macs get I was surprised to find that this Time Capsule situation didn't generate any visible errors that my wife would report to me so that I knew there was a problem.

If you've had Time Capsule issues like I have above and come up with a way to solve them that doesn't involve reformatting the TC drive and starting over I'd love to hear about it. Something tells me this may happen again.


Anonymous said…
Your wife's name is Allison Alison?
David Alison said…
@Anon: You ask that like it's an odd name or something ;-)
Anonymous said…
I have the same problem with a wired disk as my time machine drive. It keeps spinning and won't let me dismount the disk unless I restart the machine and I am not been able to access my back ups in Time Machine. I'm having no luck in straightening out the problem and cannot erase the disk because it has other important information on it. I'm not sure what to do, as Time Machine App seems highly inaccessible. Michael
Anonymous said…
I have just acquired a Time Capsule and had a similar occurrence of the perpetual "Preparing Backup..." indicator.

As I usually do I checked the Apple Support Discussion forum for Time Machine and found what seemed to fit the bill as an explanation. Sometimes the sparse image file created on the Time Capsule isn't right and Time Machine goes into a deep scan to find and correct the problem before continuing the backup.

In my case all this stemmed from a wireless network disconnect (from being too close to the Time Capsule it seems) so I hooked the Book up with an Ethernet cable to avoid this and let it do its thing and sure enough it eventually finished and completed the Backup.

Network backups make you appreciate FireWire!

Tony C.
Anonymous said…
Applications on my MacPro began freezing randomly and I was unable to get "Force Quit" to work on them and would have to force a restart by holding the power button down. After several frustrating days of problem solving, the solution turned out to be to turn off Time Machine. Turns out that my external time machine disk was nearly full and the inability of time machine to do a proper backup resulted in system wide instability. So make sure that your external drive is VERY large.
Anonymous said…
Well, it doesn't necessarily solve the problem...

But it might just help diagnose the issue...


Time Machine Reporter v1.0
Rick Baskett said…
I am not sure if it's something you would want to do, but I use a program called Time Machine Editor which allows me to set my backup schedule. I only backup once a day and I haven't had errors... well since I went to once a day :) You could try maybe 4 or more times a day, or whatever you want and maybe you'll have the same results as myself with it.
Josso said…
Please report back how she thinks of the Mac now. ;)

And: " an ability to approach any technology problem in the house and by simply laying hands on the offending device the problem is immediately solved without me doing anything."
I've tried something like that...
A friend of mine (a girl) had a problem with hers XP-notebook: It wouldn't startup.
I started it, and it haven't complained since. :p

Never tried something like that. ;p

- Johan, Denmark
Anonymous said…
I just purchased a brand new MBP with a 1TB Time Capsule, 1st thing I am in the process of doing is installing boot camp with XP. After that I am going to get the Time Capsule setup. Is there anything special I should do to make it go more smoothly?
David Alison said…
@All - thanks much for the feedback, very helpful.

@Steve: for your first backup you may want to disable the AirPort on your MBP and hook it up directly to your Time Capsule with a standard Ethernet patch cable; that first backup takes quite a while and that will speed it up considerably. Depending on the amount of data you have you may want to wait until right before you go to bed for the evening to do that first backup. The machine is usable during that time though it will go through periods of high CPU usage.

Hope that helps...
Anonymous said…
The more I hear about Time Machine the happier I am that I don't use it. A backup application isn't any good if it seriously degrades your user experience, doesn't backup when it's supposed to and creates backups that may not be readable when you need them most.

I'll stick with daily backups to a hard wired external drive using Carbon Copy Cloner.
David Alison said…
@Bregalad: I've had small problems with Time Machine on my wired up machines (mostly the often self-correcting Time Machine error); the experience I've had with the Time Capsule was much more frustrating. I love the concept of the Time Capsule and the way Time Machine works and remain a big fan of Time Machine but I do think Apple needs to do more to stabilize it as a product.
Anonymous said…
David I have had the same issue with the MBP and timecapsule, gone to the point of giving up on it and using TM to a small external HD to backup - TC seems to need considerable work yet from apple and I no longer have faith in that product, a dud in my view. Sorry cant help with a solution. It seems from the apple discussion forums thats LOTS of people experience similar wierdness. Hope some comes up with fix for you, best Mark
Anonymous said…
I agree with the Time Machine editor comment


I use this on my air as I do not need it to backup hourly etc just once every few days etc. As it is over wireless I hate time machine invoking all the time so this app was a great addition.
Anonymous said…

Not sure if you've solved your Time Machine problem at this point, and though I can't help you solve it, the folks at the Maclife forums (http://www.maclife.com/forums/) might be able to give you a hand.

Best of luck!
Anonymous said…
I had a lot of problems with an OWC NDAS drive becoming unstable when I used it for Time Machine backups. Even DiskWarrior had trouble fixing it. Finally somebody at tech support from OWC told me that it's not a good idea to put any other kind of file on a volume with a Time Machine backup on it. So I now use Time Machine only with a dedicated drive and since then I've had no trouble. Sounds like a bug in Time Machine to me, but there it is.

-- DC
Anonymous said…
There is a simple fix when you have trouble with Time Capsule back ups - Like the "can't mount the volume" error. Open the Time Capsule in the side bar and log in. Then find your back up - it will have a name like "yourmac_001f4bg4c1gf.sparsebundle". the jumble of letters is actually your Airport's "Ethernet address". Change a few letters and the next time that Time Machine runs it will start a new backup. After a couple of days you can delete the old sparsebundle. The problem occurs because the sparsebundle gets corrupt - you can fix with a Disk Utility workaround (copy it to another drive repair with DU without mounting the image) but why bother.
David Alison said…
@SH: Thanks for the tip on the MacLife forums. I've read the printed pub before but never visited the forums.

@Tim: That is very helpful, thanks man. All of these suggestions leads me to think Apple does indeed have some work to do to make Time Capsule a better product. I love the concept of seamless, wireless backup with Time Machine - it just needs to be reliable and clearly it's not right now.
mbmcavoy said…
I had a similar issue a couple weeks ago. Using Finder, opening the sparsebundle would take a lot of time verifying the file. I never did have enough patience to figure out how long it took. But cancelling the check opened the bundle anyway. I deleted in in-progress backup, but still no luck, and Disk Utility didn't help.

As Tom also suggested, I renamed the file by adding "!" in front.

Time Machine not only still found the renamed file, but successfully backed up. I renamed it back, and it's been fine since, and my backup history is intact.

I suspect the file system had some weird corruption that it didn't want to fix, but renaming the file somehow corrected it...?
Anonymous said…
my general experience with timemachine has been 'ok', nothing more. Not up to normal Apple quality of experience IMHO. But it generally works ok for me.

The biggest thing I find is that if you interrupt a backup, or if you force restart the machine (eg, occasionally I get my MBP in a state by not opening the lid cleanly. It bounces and seems to really upset the wake from sleep), then it needs to do a local spotlight rebuild and also on the timecapsule TM backup volume. I also find having it go to sleep in the middle of a backup can sometimes upset it.

This is when you see it sitting there for ages saying 'preparing backup'. I usually just connect it via ethernet and let it do its thing, and ensure that its connected to AC as well as on 'better performance' so it doesnt go to sleep in the middle of sorting its life out. Seems to go fine after that.

Overall, i think its a great tech, but it needs a few slightly ragged edges cleaned up :)
David Alison said…
@Rob: My feelings exactly. It's been stable for the last couple of days but I really would like Apple to spend some time working on the reliability and recover-ability when sparse bundle corruption occurs.
Unknown said…
> The problem occurs because the
> sparsebundle gets corrupt

This is exactly what is happening.

Why is a bit techie.

When Time Machine does a backup on a network volume, it creates a sparsebundle, which is a bit like a disk image file, a .dmg file. The sparsebundle is then mounted and is accessed more like a binary disk image, than the usual OS file read/write commands.

What this means, is that if during the backup, the network connection is broken by any means, the disk image becomes corrupt. It's kind of like disconnecting a firewire drive while the computer is writing data to it. Not only can the image's data become corrupt, but also the file directory can become damaged.

Because of the corruption, the sparsebundle has to be repaired the next time Time Machine tries to mount it. It's the same repair that you could do manually on a drive or disk image in Disk Utility. The repair requires a *lot* of disk activity. Over the network, it can take a very long time.

The Break

Breaking the network connection during backup or repair of the sparsebundle is what, for brevity, I will now call "the break."

If the break is rare, then the computer will repair the sparsebundle before the next backup. It will just take a while to do the repair. If the break happens often, then the repair will be continually interrupted, may never occur, and the corruption can get worse.

There are two common causes of the break.

The first cause is sleeping the computer and moving it away from wifi access. You should wait for the backup to finish or manually stop the backup before sleeping the computer.

The second and more destructive cause is a bad wifi connection. A bad wifi connection can cause the break to occur every few minutes. This is more common than some suspect.

A bad wifi connection is normally not noticeable because to download a web page only takes a good network connection for several seconds. You can always hit the reload button if the break occurs during a page load. To get a good backup requires a good network connection for many minutes to many hours without any breaks.

How to diagnose a bad wifi connection
method #1

Go into the Console application. It is in /Applications/Utilities. Click on the Show Log List button if the log list is hidden. Click on All messages. Search for the string "Link Down". You may see messages like:

...7:53:03p kernel AirPort: Link Down on en1
...7:55:45p kernel AirPort: Link Down on en1
...7:57:31p kernel AirPort: Link Down on en1

Messages like these should be rare. If you see multiple messages like these occurring within minutes of each other then a bad wifi connection is the problem.

How to diagnose a bad wifi connection
method #2

Another way to diagnose a bad wifi connection is to use the ping utility. You need the IP address of your Time Capsule. You can get that from the Airport Utility in /Applications/Utilities. Once you have the IP address, open Network Utility, also in /Applications/Utilities. Click on the Ping tab. Type in the IP address in the first field. Change the Send Only field from 10 to 100. Click the Ping button. Wait.... The result should be:

100 packets transmitted, 100 packets received, 0% packet loss

Anything more than a 0% packet loss indicates a bad network connection, usually a bad wifi connection. Repeat the ping test several times for good measure.

Bad wifi connections are usually caused by interference or a weak signal. Try changing the wifi channel on the Time Capsule or move the computer in relation to the Time Capsule.

Paul Russo
Mac Support
David Alison said…
@Paul: That was one of the best comments I've received on this blog and worthy of a post all it's own. Great explanation of what is going on there.

I fired up the console on my wife's MacBook and sure enough there are a full range of messages with the link down / up. I checked my MBP, which connects to the same WiFi point and it does not have any connection problems. The only link down / up pairs I see are from closing the lid and putting the machine to sleep. Ironically her machine is 3 feet away from the access point whereas mine is on a completely different floor of our house.

There hasn't been a link error in the log since yesterday afternoon. I also tried your ping technique and several 100 ping passes came up clean. I've got to think it's a localized interference problem. Before I try changing the channel I want to see what could possibly be causing this. Perhaps it's our wireless home phone or our iPhones being used next to them... not sure.

Again Paul, thanks much for the detailed explanation.
Anonymous said…
I have found that wifi devices that are too close to each other can jam each other. This could be what is happening.

Paul Russo
Mac Support
Kyle said…
I ran across this blog last week while doing research on the iMac. (I am currently pondering a switch from a Windows XP to a Mac.)

Before I found your blog, I had scheduled a Personal Shopping session at the nearby Apple Store for Saturday morning. And although your computer experience far exceeds mine, reading some of your beginning episodes (on the Mac) gives me hope as to my own learning curve if/when I make the plunge.

It has definitely shaped my understanding and questions that I should ask.

Thank you for sharing!

Anonymous said…
I have run into the same Time Capsule problem, and it appears that I cannot back up my Macbook anymore because the image is corrupted. And it appears that I do not have enough space on Time Capsule to rename the sparsebundle and create a new image (since I also back up my iMac to the same Time Capsule).

My thought was to delete the existing sparsebundle for my MacBook on the timecapsule and then start a new time machine backup using an ethernet cable instead of airport. Do you think this would work?
David Alison said…
@Ajay: I believe it will, and the direct connection SHOULD make the full backup run a lot quicker. Can you repost if that does indeed work for you?
Anonymous said…
Am so glad that I came across the comments here to help me resolve the problem with Time Machine and Time Capsule. So here's a summary of the problem I encountered and the steps I took to fix it:

1. My Time Capsule (500 GB) is the backup repository for my iMac and MB Pro.

2. On separate occasions each of the computers had problems backing up.

3. I fixed my iMac by rebooting and that resolved the problem.

4. I could not resolve the problem for my MB Pro by following all the suggestions in this thread, including renaming the sparsebundle.

5. Following David's suggestion, I turned off Airport on my MB Pro, connected my Time Capsule with an ethernet cable and deleted the corrupted sparsebundle file and started a new backup from Time Machine.

7. After the backup completed (in roughly 2.5 hours), I disconnected the ethernet cable, rebooted and did a subsequent backup successfully via Airport.

8. I downloaded Time Machine Editor and set my MB Pro to backup every 8 hours rather than every hour.

And now I have learned a lesson that I cannot interrupt my backup by closing my MB Pro in the midst of a backup.

Thanks David for the tip :)
David Alison said…
@Ajay: That's excellent man - glad this was able to help. I get a lot of hits from Google search for things like this so I'm glad to hear you were able to get a solution from the page.
otrfan said…
I had 3 machines on my TC but the "big one" was repeatedly failing. Didn't want to erase the drive and was unable to delete the sparsebundle. This tip helped but it's another example of how large backups over WiFi are problematic. I may relocate the drive to be within ethernet cable distance of the "big" machine:
Anonymous said…

I've been supremely disappointed in the Time Capsule as a product, simply because of the amount of techie knowledge it seems to require just to even operate.

I was attracted to the "wireless backup" feature, but with the complexities the TC incorporates by requiring to be the main router in my network became much more of a hassle than I was capable of dealing with.

Too bad I can't have you come over and lay your healing hands on it, like you did with your wife's. :)
David Alison said…
@David: Yeah, this is one piece of technology that Apple really needs to work on. I love the concept of Time Machine and Time Capsule; the goals of the products are dead-on. If they can get the reliability up to the point where it truly is "set and forget" then I will be very happy.
Unknown said…
Some interesting comments here about TC. I've had my 17" HighDef MBP and 1TB TC since April and it has worked flawlessly. Its sparsebundle is just under 600GB; my MBP has a 250GB hdd.

I also use my TC as a NAS - I wrote an Automator workflow to have it automatically mount when my MBP boots - to store other stuff that doesn't change all that often.

For me "it just works!".
Gary said…
I have had TC and it has been nothing but a headache, one that occurs frequently and doesn't go away easily. I would not recommend purchasing TC as the money could be better spent elsewhere. The service people are nice, but the problems are not getting fixed and the help is incosistent.
erin kistner said…
Hello David,

I have an interesting challenge for you- hopefully you can help with some of your magic! :-)
First of all, thanks to Benjamin for sharing the time machine reporter.
After running the report I received the following errors below.

I recently ran Yasu to clean my macbook and am wondering if Yasu clearing some system cache has caused this error.

Any suggestions?

Thanks so much.


Oct 30 00:00:51 Starting standard backup
Oct 30 00:01:02 Mounted network destination using URL: afp://Erin@Erins-Time-Capsule.local/Data
Oct 30 00:01:02 Backup destination mounted at path: /Volumes/Data
Oct 30 00:01:02 Cookie file is not readable or does not exist at path: /Volumes/Data/.001b63927556
Oct 30 00:01:02 Volume at path /Volumes/Data does not appear to be the correct backup volume for this computer. (Cookies do not match)
Oct 30 00:01:07 Backup failed with error: 18
David Alison said…
@Erin: It sounds like you have a file that has been left open (in this case a cookie file). Have you tried a full shutdown of both the Mac and the Time Machine drive (assuming it's external or in a Time Capsule). If that doesn't work then running Disk Utility against your Time Machine volume and asking it to repair it may help.

Also, make sure you have been applying software updates. If you are still running Leopard there were a number of patches since I posted this blog that virtually eliminated all of my Time Machine errors.

Hope this helps...

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