A few weeks back, apparently my Lumia 930 stopped backing up with the above error- it’s looking like the OneDrive backup (OneDrive > Options > Device Backups) may have become correupted. I deleted the backup for the 930, ran a fresh backup and it failed, but during the failure it switched off settings backup on the phone. I switched it back on, and now the 930 is showing up as a backup device in OneDrive. It hasn’t finished yet, but there is a backup for that device showing up in OneDrive with todays timestamp on it…
UPDATE: backup still failed, but device and OneDrive think it backed up. ?
UPDATE 22/06/2016 @ 16:44: after chatting to Microsoft a lot of the day, it seems that the problem was having the official twitter app installed- ? They pointed me at:
And although I don’t have Live lockscreen beta, the official twitter app is horrbily slow and unresponsive so I thought maybe that was worth a go (also, the icon was going dark when charging- possibly when backing up- implying it was unusable at this time, which made me think there might be an issue with it). Uninstalled twitter (still have tweetium), and have now had two successfull backups work without a problem.