Backup stuck at 25% then fails

[DreadVenom]

Hi all, I was wondering if someone could assist. I'm trying to backup my 1020 running 8.1GDR2(win insider installed & activated) but for some reason it wont complete a backup, the last successful one taking place on Saturday. I looking to update to build 10080 then onto 10149 but wanted to ensure that I had a backup of my current system.

Has anyone had this issue and know the solution??