- Open Computer.
- Right click the C drive (the active drive that contains the Windows system folder)
- Click the Shadow Copies tab
- Select the EFI volume and click settings
- Change the Maximum Size to be two or three times the size that is listed.
- If the Maximum Size is unlimited, try setting it to different values.
- Repeat steps 3 and 4 for the Recovery Partition.
Here's some background links:
https://sbsland.wordpress.com/2014/08/16/windows-server-2012-r2-backup-fails/
http://serverfault.com/questions/555912/windows-server-2012-r2-vm-back-up-fails-with-insufficient-storage-available-to-c
You can write a batch file to run these commands via the scheduler for automation,
- Disable WinRE (Open elevated command prompt and Run: “reagentc /disable”)
- Take system image backup
- Enable WinRE (Open elevated command prompt and Run: “reagentc /enable”)
https://social.technet.microsoft.com/Forums/en-US/7373a7b8-01c8-4e2b-aaaa-513b7dad56f4/windows-server-2012-r2-vm-back-up-fails-with-insufficient-storage-available-to-create-either-the?forum=windowsbackup
The "USN journal" fix does not work on 2012, since Windows Server 2012 does not allow you to assign the EFI or Recovery partitions a drive letter. But also I have not tinkered with diskpart to see if it's possible via the command-line.
Apparently there is an errant Windows Update that just recently came out, since many people are having this issue but there's no official hotfix.