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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Time Machine can no longer find backup disk

I have a USB drive hooked up to my airport extreme that I used to use as a TimeMachine backup for my MacBook Pro. I use another external drive to back up my iMac, but it is connected to the iMac directly. The drive on the airport extreme used to back up my MacBook Pro flawlessly. Suddenly, about a week ago it stopped recognizing it as a TimeMachine back up drive. I can access the drive via both my iMac and MacBook Pro and I have a small data base that I use on both Macs there as well as the "sparse bundle.." back up for the MacBook Pro. I go to TimeMachine preferences and "select backup drive". Highlighted is the external drive on the airport extreme. Underneath on the list is the red "do not enter" sign and NONE. But only the drive is in blue. I select and it begins a countdown to back up on the drive (even says the name of the drive name and location "airport extreme".) But when the back up begins it quits and gives me the message "Back Up disk not available". But I can go to that drive and open up the small data base that is there, immediately.
I have now deleted the sparsebundle from that drive and tried to start over, but for some reason it can't use that drive for back ups. What could have changed to make this drive "not available" as a TimeMachine back up?

iMac intel 24" 3.06 GHz 4 GB ram 500 GB drive, Mac OS X (10.6.4), DSL (att.yahoo) two external hard drives 250,1000 GB wireless internet Airport E

Posted on Jul 4, 2010 11:53 AM

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13 replies
User profile for user: Pondini
Pondini
User level: Level 8
38,863 points

Jul 4, 2010 1:05 PM in response to Ron Bird

Backing-up via an Airport Extreme is "iffy" and +*not supported by Apple.+* See Using Time Machine with an Airport Extreme Air Disk (or use the link in *User Tips* at the top of this forum).

Try connecting the drive directly to your Mac, and doing a +*Repair Disk+* (not permissions) on it via +Disk Utility+ (in your Applications/Utilities folder).

Then re-do the setup, per #Q2 in +Using Time Machine with an Airport Extreme Air Disk.+
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 4, 2010 2:47 PM in response to Pondini

Did as suggested. Exact same results. Backup Disk not available. Did notice that this drive only appears in TimeMachine list of discs when I open the drive to access my data file. If I don't open the drive, it's not listed in TimeMachine.
To open the drive I click Macintosh HD. On left column choose "airport extreme". Window opens and drive is listed (kind: shared) and then click the drive to access the file I wanted.
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User profile for user: Pondini
Pondini
User level: Level 8
38,863 points

Jul 4, 2010 3:07 PM in response to Ron Bird

Ron Bird wrote:
Did as suggested. Exact same results. Backup Disk not available. Did notice that this drive only appears in TimeMachine list of discs when I open the drive to access my data file. If I don't open the drive, it's not listed in TimeMachine.


That's correct. The sparse bundle containing network backups is mounted by Time Machine while a backup is running (or you enter the "Star Wars" display), then dismounted.

Did you try the +*Repair Disk?+*
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 4, 2010 9:03 PM in response to JaimieV

How can I select that drive when it is not listed. It's only in the list when I open it. Yes, I did connect it directly to the MacBook Pro and did a "Repair Disc" via Disc Utilities. At first it gave me errors and said I would have to reformat the drive. Tried a second time and it repaired the drive and said it was now OK. Checked a third time and it said drive was OK. Put the drive back on the Airport Extreme and when I went to TimeMachine preferences and Select Drive, no drive was listed. Opened the drive looked at the small database kept there and when I did, the drive magically appeared in the list of drives for TimeMachine to use.
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User profile for user: Pondini
Pondini
User level: Level 8
38,863 points

Jul 5, 2010 7:35 AM in response to Ron Bird

Ron Bird wrote:
Sorry to have ended so quickly. After doing the whole repair thing


Try repairing the +sparse bundle,+ not just the partition. With the disk connected directly, drag the sparse bundle into Disk Utility's sidebar, select it, and click +*Repair Disk.+*

and re-connecting the drive and going to TM I did select the drive (after opening it up and it appearing in the list) and then it went to the 120 second countdown BUT after the time expired I got the same message that the drive was unavailable.


Are you connected via Ethernet or WIFI? If WIFI, try Ethernet. If that works, you've probably got a WIFI problem.

If it happens over Ethernet, the combination of the problems repairing it, and not being able to connect to the sparse bundle once it was repaired, may mean the drive is failing. How old is it?

And, don't forget, backing-up this way is "iffy" and +*not supported by Apple.+* I've had exactly the same scenario occur; in my case it worked fine for about 3 months, then every few days the sparse bundle would come up corrupted. On occasion Disk Utility could fix it, on occasion Disk Warrior could, but usually I had to erase and start over. That went on for a couple of weeks; since then it's been fine, although very slow on occasion. That's all with the same hardware in the same locations, and a very good WIFI connection. If you browse the +Airport Extreme+ forum (in the +Digital Life+ section at http://discussions.apple.com/forum.jspa?forumID=1135 , you'll see a number of similar stories.

That's why I don't recommend it, and keep secondary backups as well.
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 5, 2010 8:52 AM in response to Pondini

As I said earlier, I deleted the sparsebundle completely thinking it was probably corrupted and decided to start over with a new backup, but the TimeMachine on the MacBookPro won't recognize the drive or something because even without a sparsebundle file on the external drive it won't create a new one because it says the drive is "unavailable". My connection is Ethernet to the the airport extreme via DSL modem.
I may just hook the drive (which is only a couple of months old) directly to the MacBookPro and backup manually whenever I can. Of course the portability of the MacBook will be limited during the backup process. I haven't decided, yet.
I tried to make a back up using TM from my iMac by changing the desired backup drive to the Airport Extreme connected drive just as a test and it, too, failed with the same message that the drive was unavailable after the 120 second countdown.
'Tis probably something in the setup of the airport-MacBook-iMac configuration that I don't really understand.
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 6, 2010 11:46 AM in response to Ron Bird

Well as a hopefully temporary solution, I re-partitioned the drive and hooked it up directly to the MacBookPro and TimeMachine is currently making a backup of the system. But, of course, that solution will only work when the drive is connected directly to the computer making it non-portable for that time. At least I will have a backup that I can occasionally update when I connect the drive to the MacBook.
Before I did that I tried once again to use the airport extreme connection and again after the countdown it gave me the error that the drive was unavailable. It used to work fine, but something must have changed.
Several months ago I had to do a complete restore using TimeMachine since the computer would not boot at all. After the restore everything seemed back to normal an I lost very little except a few advertising ads in my email account. I'm sure TimeMachine was working after the restore or I would have noticed the error messages. This stopped working about 10 days ago or so. Would like any advice on what to do.
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 6, 2010 1:55 PM in response to Ron Bird

One more item. I took another drive and tried to use it on my MacBookPro and iMac via airport extreme and back up using TimeMachine, but got the same error; backup drive not available. But I took that drive (still connected to airport extreme) and used it to back up an older Power iMac that was connected to the airport extreme and it backed up the old iMac using TimeMachine on that iMac. So the problem is the wireless connection between the airport extreme and my other two Macs. Just another clue.
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User profile for user: Ron Bird
Ron Bird Author
User level: Level 1
20 points

Jul 7, 2010 8:34 AM in response to Ron Bird

I may have solve the problem. I used the Airport Utility and gave the airport extreme a new password. Had to restart the computer to get it to work on that computer. But magically now all my computer will be able to back up wirelessly to that drive. Only my MacBook needs it, though.
Be careful when assigning which drive to use in TimeMachine. When it says it needs your user name and password for the extreme it means your user name for the computer you are on AND the PASSWORD for the Airport Extreme, not the password for your computer.
Whew!!! Thanks for the help Pondini.
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Time Machine can no longer find backup disk

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