Problem Description :
Your backup can fail if you try to create a system image in Windows 8.1 with the mentioned below error message. We saw the same error message in Windows 7, 8 and 8.1. Even if, different versions of Windows shows the same error message, the root cause is different on each one. I will give you later more information about why Windows 8.1 fails during system image creation. Basically you can apply the mentioned below action plan to be able to successfully create a system image.
Error Message :
The backup failed. There is not enough disk space to create the volume shadow copy on the storage location. Make sure that, for all volumes to be backup up, the minimum required disk space for shadow copy creation is available. This applies to both the backup storage destination and volumes included in the backup. Minimum reqirement: For volumes less than 500 megabytes, the minimum is 50 megabytes of free space. For volumes more than 500 megabytes, the minimum is 320 megabytes of free space. Recommended: At least 1 gigabyte of free disk space on each volume if volume size is more than 1 gigabyte. (0×80780119)
1) Open a CMD window as administrator and type > reagentc /disable
2) Create your system image
3) Enable Windows RE again by typing > reagentc /enable
You can basically check with the following command if reagentc is enabled or not. Type > reagentc /info. ReAgentc basically enables Windows Recovery Tools partition which is also visible on the below screenshot.
Note : In case of you recover your Operating System from the System Image you created above you need to enable ReAgentC again, afterwards.
Hope it helps.