TIH 2011 - problem restore from non-credentialed network share

I have TIH installed on a Win7 Pro x64 system. It has been running nightly disk image full backups of the OS (C:) drive to a network share that does not require credentials for about a year without issue.

A couple weeks ago the system started BSDing as soon as the desktop & startup apps finished loading. When I tried to restore the drive from stand-alone TIH at boot, it refused to retrieve the backup files without credentials. TIH browsed to the file location on the NAS without issue, but every time I selected a backup image, the credentials window would open. No matter if I closed or cancelled the window, submitted it blank or tried entering my computer user login, TIH would not retrieve the file. Since the system would boot into safe mode, I was able to copy the backup images from the NAS to my D: drive so I could access them with TIH in boot mode.

Now that I have reinstalled Windows (all 10 days of backup images crashed with same issue, so restore wasn't possible) & have the system running again, what do I have to do so I don't encounter this same problem accessing the backup images in the future? Is there something I should set when creating the backups?

Thanks!