Time Machine Unable to Connect to Time Capsule

[RossW]

Since last Friday (11-Nov-2016) Time Machine has been unable to back up my iMac. When I try to run backup manually I get an error message that says "Time Machine couldn't complete the backup to TC. The backup disk is not available. Make sure the backup disk is connected or select a different backup disk". Originally, when I opened AirPort Utility the TC had a yellow light but after restarting the TC it is now green; I can edit the info but that hasn't made any difference. What's weird is that I also backup my MacBook pro to the same TC over WiFi and that works fine; I just did a manual backup this morning and that completed normally. The router part is working fine; I'm connecting my iMac via cable and everything else via WiFi and no problems.

• I can access the disk via Finder and open the Data volume and can see the backup sparse bundles, and open them too

• I cannot get to the backup via Time Machine, nor will Verify Backup work (same error message)

• I can't see the TC disks from Disk Util

• I don't have anything configured under Back to my Mac

iMac (Retina 5K, 27", Late 2014)
OS X El Capitan (10.11.6)
AirPort Time Capsule (3 TB - no idea what generation it is since holding down the option key while opening AirPort Utility didn't give me any summary info)

I've googled the error message and everything I've seen talks about problems with Back to my Mac. That's not the case for me.

Any help would be very much appreciated.

 

[michelangelo]

If not solved already, try this.

We will assume (1) your Time Capsule is fine (as attested by your continuing backup of your MacBook) and (2) your iMac's Time Machine has lost its secure access to your Time Capsule, in spite of the fact, seen from the iMac's Time Machine Preference window, the time Capsule's drive "Data" shows (which you have *not stated nor denied).

To save process time, connect your iMac to your Time Capsule LAN port (one of the three LAN ports) by an ethernet cable and cut wifi off. Verify that you are still connected to the Time Capsule (Airport utility, time Machine Prefs). If you stay, instead, on wifi rather than ethernet, it will work also, just more slowly. Do that before going to bed.

On your iMac, Open Time Machine Preferences... > Click "Add or remove backup disks" > Under "Backup disks", "Data" should appear (on top), select "Data", click "Remove".

Your Data drive is no longer selected by time Machine. But, as you mentioned, your iMac sparse bundle is still there, alive and correctly identified in the Data drive. This is what matters here.

Open Time Machine Preferences... > Click "Add or remove backup disks" > Under "Available disks", "Data" should [still] appear, select "Data", click "Use disk". You will (may) be asked your Time Capsule's password. This is to authorise access. [with luck] Time Machine will start working. Don't worry, it will not recreate a new backup blob but it needs time to connect itself to the existing sparsebundle and fully understand whatever it contains, then it needs time to complement it and bring it current.

Go to bed...

Tomorrow, it will have (hopefully) recovered and will resume doing its hourly backups. If not, go to a genius bar with your iMac and your time Capsule.

In any event, please tell us how it went. HTH

 

[RossW]

If not solved already, try this.

We will assume (1) your Time Capsule is fine (as attested by your continuing backup of your MacBook) and (2) your iMac's Time Machine has lost its secure access to your Time Capsule, in spite of the fact, seen from the iMac's Time Machine Preference window, the time Capsule's drive "Data" shows (which you have *not stated nor denied).

To save process time, connect your iMac to your Time Capsule LAN port (one of the three LAN ports) by an ethernet cable and cut wifi off. Verify that you are still connected to the Time Capsule (Airport utility, time Machine Prefs). If you stay, instead, on wifi rather than ethernet, it will work also, just more slowly. Do that before going to bed.

On your iMac, Open Time Machine Preferences... > Click "Add or remove backup disks" > Under "Backup disks", "Data" should appear (on top), select "Data", click "Remove".

Your Data drive is no longer selected by time Machine. But, as you mentioned, your iMac sparse bundle is still there, alive and correctly identified in the Data drive. This is what matters here.

Open Time Machine Preferences... > Click "Add or remove backup disks" > Under "Available disks", "Data" should [still] appear, select "Data", click "Use disk". You will (may) be asked your Time Capsule's password. This is to authorise access. [with luck] Time Machine will start working. Don't worry, it will not recreate a new backup blob but it needs time to connect itself to the existing sparsebundle and fully understand whatever it contains, then it needs time to complement it and bring it current.

Go to bed...

Tomorrow, it will have (hopefully) recovered and will resume doing its hourly backups. If not, go to a genius bar with your iMac and your time Capsule.

In any event, please tell us how it went. HTH

Thanks Michelangelo. I appreciate your very detailed instructions. I resolved the problem only by re-formatting the TC hard disk (not using Quick Erase) and starting again. I gave the disk a different name than before because keeping it the same didn't seem to work. I had contacted Apple Support and they couldn't figure it out, but it just magically started working after a while. It's entirely possible your solution may have worked.

 

[michelangelo]

Thanks Michelangelo. I appreciate your very detailed instructions. I resolved the problem only by re-formatting the TC hard disk (not using Quick Erase) and starting again. I gave the disk a different name than before because keeping it the same didn't seem to work. I had contacted Apple Support and they couldn't figure it out, but it just magically started working after a while. It's entirely possible your solution may have worked.

I am glad to hear your difficulty got sorted out, not the best way, but sorted out nevertheless. I am a huge fan of the Time Capsule (TC) but believe nevertheless it is very weak, principally its "Data" drive, which you cannot evaluate with DriveDX nor repair with disk utilities or other. I also experienced the need for a complete wipe of the Data drive and was quite unhappy about it. Some on this forum distrust completely the TC, not me. But I use two drives: the "Data" drive and an external USB2 drive which is partitioned: one partition per mac (two macs). Both macs backup in the single "Data" internal TC drive. So each mac is backed up twice: once on the Data drive and once on its personal partition on the drive attached to the TC. I want to keep a minimum 12 months history on Time Machine (TM). This is a lot, 6 months should be enough. I also want to wipe erase these drives from time to time to minimise the probability of a TM failure (with normal wear and tear on the TC's platters, TM can get lost in its hierarchy of hard links). So, whenever both drives have reached 12 months, I erase and reformat (with one pass of zeroes as I believe you did) the oldest (which contains then more than 12 months). Since Disk Utility cannot reach the Data drive, cleaning it up with one pass of zeroes is the best way I have heard of to force the Data drive to rejuvenate itself and take care of all of its bad blocks. HTH

 

[RossW]

I am glad to hear your difficulty got sorted out, not the best way, but sorted out nevertheless. I am a huge fan of the Time Capsule (TC) but believe nevertheless it is very weak, principally its "Data" drive, which you cannot evaluate with DriveDX nor repair with disk utilities or other. I also experienced the need for a complete wipe of the Data drive and was quite unhappy about it. Some on this forum distrust completely the TC, not me. But I use two drives: the "Data" drive and an external USB2 drive which is partitioned: one partition per mac (two macs). Both macs backup in the single "Data" internal TC drive. So each mac is backed up twice: once on the Data drive and once on its personal partition on the drive attached to the TC. I want to keep a minimum 12 months history on Time Machine (TM). This is a lot, 6 months should be enough. I also want to wipe erase these drives from time to time to minimise the probability of a TM failure (with normal wear and tear on the TC's platters, TM can get lost in its hierarchy of hard links). So, whenever both drives have reached 12 months, I erase and reformat (with one pass of zeroes as I believe you did) the oldest (which contains then more than 12 months). Since Disk Utility cannot reach the Data drive, cleaning it up with one pass of zeroes is the best way I have heard of to force the Data drive to rejuvenate itself and take care of all of its bad blocks. HTH

Thanks Michelangelo. I love my TC and the Time Machine capability but found that after moving to a new iMac that restoring from a backup did not recreate all docs as I'd hoped. It was lucky I kept the old iMac around and was able to find the missing docs on that and copy it over manually. Because of that case, I bought Carbon Copy Cloner and clone my iMac/Macbook to an external drive periodically, just in case something catastrophic happens and I really need to find something that TM doesn't have.

 

[Slydude]

General info for the thread

You cannot use Disk Utility to examine a Time Capsule's hard drive but there is something that can be done using Disk Utility. I discovered this by accident/desperation one day,
1. Open the Time Capsule so that you can access the sparsebundle Time Machine has created.
2. Double-chick the sparsebundle. It should now appear as a disk drive in the Finder.
3. Launch Disk Utility and select the drive that was just created in step 2.
4. You should now be able to run Disk Utility and repair any errors that are found.

 

[michelangelo]

Good to Know, thanks