Backups failing with error 19: the backup disk could not be resolved, or there was a problem mounting it

Yosemite is problematic on two fronts.. Networking and Time Machine.. so the combo of doing both with a Time Capsule is like bugs on bugs.

Here is my standard list.. but your problem maybe difficult to resolve.. and my suggestion is simple.. until Apple get their act together and fix TM.. buy Carbon Copy Cloner and use that for your backup. It is solid and reliable.. even better if you use USB drive plugged into the computer and do a bootable clone.. because then you have a backup that is able to be tested for full functionality 2min after the end of the backup.

This also starts from a factory reset.. but the reason for it is to change the configuration which is much more easily handled with factory reset to begin.. the instructions are there.. because this is my standard reply.. this is not uncommon!!

Factory reset universal

Power off the TC.. ie pull the power cord or power off at the wall.. wait 10sec.. hold in the reset button.. be gentle.. power on again still holding in reset.. and keep holding it in for another 10sec. You may need some help as it is hard to both hold in reset and apply power. It will show success by rapidly blinking the front led. Release the reset.. and wait a couple of min for the TC to reset and come back with factory settings. If the front LED doesn’t blink rapidly you missed it and simply try again. The reset is fairly fragile in these.. press it so you feel it just click and no more.. I have seen people bend the lever or even break it. I use a toothpick as tool.

N.B. None of your files on the hard disk of the TC are deleted.. this simply clears out the router settings of the TC.

Setup the TC again.

ie Start from a factory reset. No files are lost on the hard disk doing this.

Then redo the setup from the computer with Yosemite.

1. Use very short names.. NOT APPLE RECOMMENDED names. No spaces and pure alphanumerics.

eg TCgen5 and TCwifi for basestation and wireless respectively.

Even better if the issue is more wireless use TC24ghz and TC5ghz with fixed channels as this also seems to help stop the nonsense. But this can be tried in the second round.

2. Use all passwords that also comply but can be a bit longer. ie 8-20 characters mixed case and numbers.. no non-alphanumerics.

3. Ensure the TC always takes the same IP address.. you will need to do this on the main router using dhcp reservation.. or a bit more complex setup using static IP in the TC. But this is important.. having IP drift all over the place when Yosemite cannot remember its own name for 5 min after a reboot makes for poor networking. If the TC is main router it will not be an issue.

4. Check your share name on the computer is not changing.. make sure it also complies with the above.. short no spaces and pure alphanumeric.. but this change will mess up your TM backup.. so be prepared to do a new full backup. Sorry.. keep this one for second round if you want to avoid a new backup.

5. Mount the TC disk in the computer manually.

In Finder, Go, Connect to server from the top menu,

Type in SMB://192.168.0.254 (or whatever the TC ip is which you have now made static. As a router by default it is 10.0.1.1 and I encourage people to stick with that unless you know what you are doing).

You can use name.. SMB://TCgen5.local where you replace TCgen5 with your TC name.. local is the default domain of the TC and doesn't change.

However names are not so easy as IP address.. nor as reliable. At least not in Yosemite they aren't. The domain can also be an issue if you are not plugged or wireless directly to the TC.

6. Make sure IPv6 is set to link-local only in the computer. For example wireless open the network preferences, wireless and advanced / TCP/IP.. and fix the IPv6. to link-local only.

There is a lot more jiggery pokery you can try but the above is a good start.. if you find it still unreliable.. don't be surprised.

You might need to do some more work on the Mac itself. eg Reset the PRAM.. has helped some people. Clean install of the OS is also helpful if you upgrade installed.

Tell us how you go.

Someone posted a solution.. See this thread.

Macbook can't find Time Capsule anymore

Start from the bottom and work up.. What I list here is good network practice changes but I have avoided Yosemites bug heaven.

This user has had success and a few others as well.

RáNdÓm GéÉzÁ

Yosemite has serious DNS bug in the networking application.. here is the lets say more arcane method of fixing it by doing a network transplant from mavericks.

http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-yo u-can-do-to-fix-it/

Your problem is as expected.. it is pure yosemite..

But please tell me full network layout and what else you have around the place.. ie NAS wasn't listed before.

What is the modem?

Is it router or is the TC router?

Please post screenshots of the TC setup.. only with that can I get the info I need.

Your current setup is ok.. I don't like the name.. because you have a space.. but I am being over pedantic perhaps.. ie I doubt the name is the issue.

Step 5: I tried but it errored out with : There was a problem connecting to the server 10.0.1.1 The share does not exist on the

server. Please check the share name, and then try again

This is the serious one..

Is the TC on 10.0.1.1 and if so there is NO WAY it should not mount.

If you reboot the TC test it then.. I am sure it will mount.. tell me how long it lasts after you manually mount it.. That is the DNS btw..

Is the computer name changing.. please open the preferences and check the share name.. does it have a number in brackets after it.. that is bad sign if it does.

I’m not on a Macbook but iMac - not sure if that makes a difference

Makes no difference.. but use ethernet if you can..

And to be honest if you use desktop computer use USB drive plugged into it.. TM is much more reliable to local cf network drive. This is network problem.. plus TM.. but network in your case is the key one.

Can you tell me if once this is fixed, will all the OLD backups from Mavericks be good or LOST?

The old backup should be fine.. but did you upgrade install Yosemite over the top of Mavericks then use TM and backup over the top of the existing backup.. if you did that You cannot revert to Mavericks.. AFAIK Yosemite will stop any reversion happening.. but all your apps and files should be ok..

TM backup should be archived before you load Yosemite over the top or you should make a clone.. since upgrade install is such a major change to the computer.

I don't see anything wrong.

I guess my only concern is the search domain that your ISP is passing to you.. I am just not sure what effect that will have.. but it should not affect the mounting of the disk.

Try again with Finder..

Use Go, Connect to Server.

If the above command fails.. hmmm.. try AFP://10.0.1.1 or even CIFS://10.0.1.1

One of those should work.. if it fails something has gone wrong in the install on the computer.

Please turn off the wireless connection at some point when testing.. just use ethernet not both.

Even though ethernet is correct in being the top of the list, it can still have issues having two connections.

Just tell me how it goes.

AFP did not work but CIFS did - what does that tell you

The network gremlins are out in force.

CIFS is simply SMB v1 .. SMB defaults to v2.. but it is known to be buggy.

Try what apple said and turn off the my cloud.. then reboot the whole network and try to mount again using SMB.

But I would not over worry now.. If neither protocol works ie SMB or AFP it is no wonder TM has issues.

Your whole network is having major issues.. and the fix is probably a clean install of the OS...

But start with simplest network possible.. modem.. plus TC plus computer.. then see if you force the connection in Finder to the TC. If it works.. reset TM and start over.. direct it to the TM and even if you have to start a new backup using a different short simple name on the computer..

Sometimes these things take more time and effort to fix than it is worth.. like buy CCC and forget this.

I cannot think of anything else at the moment.. post again when you get some info..

Time to use Carbon Copy Cloner and give TM a rest methinks.