Hi Dj
Thanks for posting.
Can you post the last few lines of your backup log with the error so we can see the exact error text and context?

Above is the entry in MR, showing the 'Error' under Last Result...
This is the VSS Log (if that's the 'Log' you mean?) -
=====
(Gathering writer metadata...)
(Waiting for the asynchronous operation to finish...)
Initialize writer metadata ...
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
Discover directly excluded components ...
- Excluding writer '' since it has no selected components for restore.
- Excluding writer '' since it has no selected components for restore.
- Excluding writer 'Shadow Copy Optimization Writer' since it has no selected components for restore.
- Excluding writer 'MSSearch Service Writer' since it has no selected components for restore.
Discover components that reside outside the shadow set ...
- Component '\TasksStore' from writer 'Task Scheduler Writer' is excluded from backup (it requires C:\ in the shadow set)
- Component '\WriterMetadataStore' from writer 'VSS Metadata Store Writer' is excluded from backup (it requires C:\ in the shadow set)
- Component '\PerformanceCounters' from writer 'Performance Counters Writer' is excluded from backup (it requires C:\ in the shadow set)
- Component '\Registry' from writer 'Registry Writer' is excluded from backup (it requires C:\ in the shadow set)
- Component '\COM+ REGDB' from writer 'COM+ REGDB Writer' is excluded from backup (it requires C:\ in the shadow set)
- Component '\WMI' from writer 'WMI Writer' is excluded from backup (it requires C:\ in the shadow set)
Discover all excluded components ...
Discover excluded writers ...
- The writer 'Task Scheduler Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
- The writer 'VSS Metadata Store Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
- The writer 'Performance Counters Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
- The writer 'Registry Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
- The writer 'COM+ REGDB Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
- The writer 'WMI Writer' is now entirely excluded from the backup:
(it does not contain any components that can be potentially included in the backup)
Discover explicitly included components ...
Verifying explicitly specified writers/components ...
Select explicitly included components ...
Creating shadow set {6ff739f6-34cc-4712-9dac-198fa02d1961} ...
- Adding volume \\?\Volume{97608ee6-e436-11e4-8235-6036ddf509e2}\ [D:\] to the shadow set...
Preparing for backup ...
(Waiting for the asynchronous operation to finish...)
(Waiting for the asynchronous operation to finish...)
Creating the shadow (DoSnapshotSet) ...
(Waiting for the asynchronous operation to finish...)
(Waiting for the asynchronous operation to finish...)
Shadow copy set successfully created.
Saving the backup components document ...
List of created shadow copies:
Querying all shadow copies with the SnapshotSetID {6ff739f6-34cc-4712-9dac-198fa02d1961} ...
* SNAPSHOT ID = {cb43de22-bb81-43d3-90d6-24fdc03bd781} ...
- Shadow copy Set: {6ff739f6-34cc-4712-9dac-198fa02d1961}
- Original count of shadow copies = 1
- Original Volume name: \\?\Volume{97608ee6-e436-11e4-8235-6036ddf509e2}\ [D:\]
- Creation Time: 8/23/2017 7:15:24 PM
- Shadow copy device name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy9
- Originating machine: David-PC
- Service machine: David-PC
- Not Exposed
- Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
- Attributes: Auto_Release Differential
=====
Hope this helps...!