I am trying to create a scheduled backup on a Server 2008 R2 box (using the built-in Windows Server Backup UI). Whenever I run a backup manually (image or otherwise), it works perfectly. When I try to schedule the same backup I get all the way to the end and it pops up an error saying:
Logon failure: unknown user name or bad password
I'm copying to a network drive via a UNC path, but I've confirmed the user/pass I'm entering there are correct (if entered wrong it immediately prompts again). Once this error pops up, I hit OK and the status just says "The backup schedule was not created."
As a final note, this had been tried under both the built-in administrator account and a separate admin account. It's a standalone box (no domain) and both accounts I've tried under are part of the local Administrators group.
I believe (but don't quote me) that Windows Backup on Windows Server 2008 R2 uses the task scheduler. You should be able to check the task scheduler and set which login account the scheduler is using. It might just need the password. Though typically it will run under a "system account", that has the necessary privledges.
You will probably need to find an account that has access to the UNC and has local admin privledges on the box you are backing up. I believe that you can use teh same username and password on both and it should work so long as you set the Username and password in the task manager to match.
Have you tried using the CLI c:\windows\system32\wbadmin.exe? I backup to a share which I give to wbadmin.exe on the command line, with a username and password. I use Bacula as the scheduler, but you could create your own task in Task Scheduler.
The CLI version is also a lot more verbose, or so it seems as you get a chronology of status messages and path to two files at the end, one containing output (stdout in Unix) log and another error logs.
One other thing to consider when using Windows Server Backup is that you cannot backup less than once a day, for example once every two days. By using the command line you can choose to do backup however less frequently you want! Remember that with backups to a share, you do not get incremental backups. The latest backup overwrites the past backup and consequently if your latest backup is stuffed, so is your only backup of the server.
This might all be advice that you've heard before. My 2c of experience as I've just finished setting up backup in my infrastructure with too-many-to-count W2K8R2 and W7Pro machines.