Windows 8.1 Insufficient storage available to create shadow copy

Burned an MSDN tech support incident and just got off the phone with the support engineer. He reproduced this problem on a UEFI system with Windows 8.1 installed. It turns out that the -AllCritical qualifier to the wbAdmin command does not work on a UEFI system because Volume Shadow Service (VSS) can not create a shadow copy of the FAT32 EFI partition.

The solution is to explicitly back up the C partition (without the -allCritical option):

wbAdmin start backup -backupTarget:E: -include:C:

You can ignore the warning that "this backup cannot be used to perform a system recovery". Both the Recovery and EFI partitions are restored during the system restore operation. (Makes sense... they were created during the initial system installation, so Windows obviously knows how to create them again.)

Some notes related to this issue:

1. Note that the "Recovery" partition is a misnomer. That partition is actually the boot partition. In a legacy (non-UEFI) system, the "System reserved" partition serves the same purpose.

2. To manage the files on the "backup" drive, use the vssadmin command line tool. Specifically:

   • vssadmin list shadows shows the show copies (i.e. "backups") stored on your backup drive. Note that, while a backup is in progress, the shadow copy is listed as being on the drive being backed up. The backup operation first creates a volume shadow copy on the volume being backed up, and them moves the shadow copy to the backup drive.

   • vssadmin delete shadows lets you selectively delete old shadow copies from your backup drive.

3. To restore a partition, attach the backup disk and boot from the Windows 8.1 distribution media. Select "Repair your computer", then "System image recovery". When the restoration process is done, your EFI and Backup partitions are also restored. (Or at least so claims the Microsoft engineer. I have not verified that this is correct.)

4. Here are some links (courtesy of the Microsoft tech support guy) that may be helpful:

   • Differences between UEFI vs. Legacy BIOS boot install
   • Recommended UEFI-Based Disk-Partition Configurations
   • Windows and GPT FAQ
   • Windows Server Backup Overview
   • Windows Server Backup Command Reference
   • What's New in Windows Server Backup
   • Install Windows Server Backup Tools
   • Optimizing Backup and Server Performance
   • Wbadmin start systemstatebackup
   • Permissions and user rights required to back up and restore
   • How Volume Shadow Copy Service Works
   • Volume Shadow Copy Service

Edit:

I've discovered that System Image Backup is, in fact present in Windows 8.1; bring up Control Panel/File History, and the link is at the bottom left corner of the window. Scott Hanselman has a blog entry on the subject.