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Level 1

4 points

Time Machine couldn’t complete the backup

After upgrading to El Capitan and Server 5.x, my client machines can no longer use the server as a Backup destination. I get the following error:

Time Machine couldn’t complete the backup to “Server”.

The network backup disk could not be accessed because there was a problem with the network username or password. You may need to re-select the backup disk and enter the correct username and password.

I have gone as far completely wiping the drives of the server (CMD+OPT+R) via Internet Recovery and installing the OS X fresh and Server 5 fresh. I additionally attempted to add a new client machine that was just out of the box, and I get the same errors.

I am positive my username and password are correct, I am able to use the login credentials to access the disk/folder as a share.

Time Machine IS Turned ON.

Drives ARE Mapped to Time Machine in the Server OS-X Panel.

User Permissions are CORRECT to Read/Write to the Time Machine.

I have cleared out all Time Machine and Server related items in the Keychain.

Does anyone have any ideas?

Mac mini, OS X El Capitan (10.11)

Posted on Oct 4, 2015 12:06 PM

19 replies

MartyF81 Author

Level 1

4 points

Oct 11, 2015 11:56 AM in response to Joerg Fiedler

How do I open a ticket with Apple Engineers?

Oct 14, 2015 6:02 AM in response to MartyF81

Something similar has been happening to me, but I think I solved it.

After installing El Capitan on the client and Server 5.0.4 on my server, I set up the Time Machine service using a service account called, imaginatively, “Timemachine”. The first backup ran smoothly, but the second one generated the “problem with network username or password” error. Each time I started a fresh backup, e.g. using another disk or throwing away the sparse bundle on the server and reselecting the drive, Time Machine would run smoothly, but every time after that, the error would re-occur.

Linc Davis’s post made me examine the credentials in the System keychain on the client. Those turned out to be the culprit. When creating the service account, I had accepted the automatically provide account name “timemachine”, but I had used the full name “Timemachine” when connecting to the server. Somehow this seems acceptable when making the first backup, but not when connecting a second time!

After changing the account name in the System keychain from “Timemachine" to “timemachine" the error no longer pops up and backups run flawlessly.

MartyF81 Author

Level 1

4 points

Oct 14, 2015 6:30 AM in response to Roger Jolly

Wow thanks! that worked. I created a new user account where everything was lower case and magically this started working. I didn't even go into Keychain... I just made new account in lowercase. I wonder what bug caused that.

Thanks again!

Linc Davis

Level 10

209,547 points

Oct 14, 2015 4:44 PM in response to Roger Jolly

That's a fine observation.

Time Machine couldn’t complete the backup