Backup error

Hello everyone.When i take backup with dp i have an error like this:

[Major] From: VBDA@socecmdb "C:" Time: 11.11.2016 10:21:23
[81:1009] It was not possible to create volume snapshot for 'C:\'. System error: 'VSS Snapshot creation failed'.

[Critical] From: VBDA@socecmdb "C:" Time: 11.11.2016 10:21:23
Fallback to legacy filesystem backup was not allowed. Aborting the backup.

[Critical] From: VBDA@socecmdb "C:" Time: 11.11.2016 10:21:23
[81:52] /C
Not a valid mount point => aborting.

Please if someone know how to resolve this problem.Help me..

Thanks everyone