Veeam endpoint backup

[SOLVED] Veeam Endpoint Backup: 28.11.2016 16:20:44 :: Creating VSS snapshot Error: Failed to create snapshot: Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. VSS asynchronous operation is not completed.

Problem & Context:

You're using the great Veeam endpoint backup (https://www.veeam.com/free-backup) but suddenly backups stop working and you encounter the following error message: