Microsoft VSS provider by default uses the same volume for storing snapshots with the small Maximum Shadow Copy Storage space parameter value.
The vssadmin command line tool should be used to check and configure the VSS storage parameters.
First you will need to list the shadow storages by using the vssadmin list shadowstorage command. See also Microsoft TechNet: Vssadmin list shadowstorage.
In the command line (Start-Run -> cmd), issue the following command:
vssadmin list shadowstorage
You will get the list of associations:
For volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{34e2a3b2-3136-11df-81bf-806e6f6e6963}\
Used Shadow Copy Storage space: 1.815 GB (1%)
Allocated Shadow Copy Storage space: 2.315 GB (1%)
Maximum Shadow Copy Storage space: 2.419 GB (1%)
(!) If no shadow storages are specified, the operating system allocates up to 10% of the volume the snapshot is taken of.
If the volume that you back up has enough free space to store the snapshots, you can resize the shadow storage with the vssadmin resize shadowstorage command. See also Microsoft TechNet: Vssadmin resize shadowstorage.
For example
vssadmin resize shadowstorage /for=c: /on=c: /maxsize=20GB
(!) If you would like to allocate all of the volume's free space for the storage, use the unbounded value. E.g. vssadmin resize shadowstorage /for=c: /on=c: /maxsize=unbounded
You can also do the resize via Computer -> Properties -> System Protection. For details please see External Resource: Change & Limit System Restore In Windows 7.
If you need to change the current volume of where the storage is to a different one, you can do this on server operating systems with the vssadmin delete shadowstorage and vssadmin add shadowstorage commands. This will delete the current shadow storage and create a new one on the volume you specify. See also Microsoft TechNet: Vssadmin delete shadowstorage and Vssadmin add shadowstorage.
For example
vssadmin delete shadowstorage /for=c: /on=c:
vssadmin add shadowstorage /for=c: /on=d: /maxsize=20GB
As a result, all snapshot data of volume C: will be cached on volume D:.
(!) Only server operating systems support the Shadow Copy transporting functionality.
If Volume Shadow Copy Service (VSS) snapshots do not get deleted automatically after the backup, you can delete them manually:
vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=300MB (this will force the system to delete the snapshots)
vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=10240MB (after deleting the snapshots, set a maximum size limit of the total storage area that the shadow copies can occupy)