Symptoms
SQL backup fails with the following error:
Failed to create express snapshot for the backup
Cause
Paging file configured to non-boot volume (not default "C:" drive).
Acronis file tracking driver attaches to the volumes during system startup in order to track changes on the file system. Per current product design, file tracker driver assumes that boot volume is the first volume to be mounted during system startup. If other volumes were mounted before the boot volume, then the file tracker driver will not be attached to these volumes.
On modern Windows systems, a volume other than boot volume may be mounted first: if "pagefile.sys" is stored on e.g. logical drive D:\ instead of logical drive "C:\" (default behavior), then volume for "D:\" will be mounted before "boot volume" ("C:\") during system boot initialization process. As a result, changes on drive D:\ will not be monitored by Acronis driver, resulting in the above error during backup.
This behavior will be changed in upcoming product update.
Solution
Сonfigure the pagefile.sys to be saved on boot volume ("C:") and reboot the system, then reattempt the backup.