Error code 0x8004231f indicates VSS_E_INSUFFICIENT_STORAGE (Insufficient storage space for the Shadowcopy). Macrium Reflect uses shadow storage space for system restore points. It is likely that either you have inadvertently allocated a drive letter to the Microsoft System Reserved partition (MSR), or you have too many restore points on your system.
You may also see the following errors in your backup log:
There are 3 solutions to this error.
Remove drive letters allocated unnecessarily to small partitions:
The MSR partition is required to boot Windows 7 and later operating systems. Ordinarily, this partition does not have a drive letter assigned to it. If a drive letter is assigned then this can cause problems with Microsoft Volume Shadow copy Service (VSS).
The same is also true of Original equipment manufacture (OEM) utility and recovery partitions such as DELL utility partitions. These partitions also do not require drive letter associations and allocating a drive letter can cause VSS to fail.
For more information on correcting this see article: Removing a drive letter from the MS System Reserved partition
Increase shadow storage space:
To see the amount of storage space allocated and used for Volume Shadow Copies run this command from a command prompt with elevated privileges:
To allocate more storage (e.g. 50GB) run this command:
Remove old VSS snapshots:
During normal Windows operation, restore points are created during software installation and other regular operational tasks. These restore points create snapshots that reside in an area of the disk and consume disk space.
Reclaim this disk space by using the vssadmin command in an elevated MS-DOS command prompt. Running an elevated command prompt
Enter the following command:
This removes all VSS snapshots on the system, prompting you for confirmation.
Run the command vssadmin list shadows to display a list of snapshots on your system with associated IDs. Deletion by ID must specify a valid snapshot ID, deletion by volume must specify a valid Windows volume (e.g.: C:) and deletion of oldest snapshot simply removes the single, oldest snapshot on the system. An example of deleting by ID follows:To not be prompted by any of the commands use the /quiet flag.
This Microsoft KB article provides further information regarding vssadmin list shadows.
This Microsoft KB article provides further information regarding vssadmin delete shadows.