Just 2 easy steps to unsnap the snapshot on the Datto SIRIS

by Sep 27, 2012Business Continuity

Do you know how to unsnap the snapshot on the Datto SIRIS?

Unsnap the snapshot on your Datto SIRIS in just a couple of easy-to-follow steps. Just watch the below or read our post!

Errors will occur when backing up with any (and every) solution.  Knowing how to resolve those errors and issues is critical too ensuring your backup and recovery solution is successful.

Below is a possible error you may encounter with a Datto SIRIS solution:

VSS failure occurred mid transfer.
stcx.SnapshotError (rc=500, err=1): Could not unsnap the snapshot. (-2147212543, False); None.


The Microsoft Shadow Copy Provider responsible for VSS was unable to perform a backup.

Note: Backups will continue if this error is thrown, unless the StorageCraft Shadow Copy Provider is not running. The StorageCraft Raw Agent Service uses both the Microsoft Shadow Copy Provider VSS and Storage Craft Shadow Copy Provider (STC) to perform backups.  If the Microsoft Shadow Copy Provider fails then this error will appear, and the next backup will be attempted by the Storage Craft Shadow Copy Provider (STC).  The STC backup produces a crash consistent state backup, whereas fully functional VSS writers produce an application aware backup.  This is a concern for systems running any services that include a VSS writer for backups, such as database services.  For instance, if the VSS writer for a database is failed, recent transactions for that database may not be backed up by ShadowSnap.


Suggested long-term resolution path

Windows 2003 and older:  Update the Protected Machine with all hotfixes that are available for VSS from Microsoft. Check the VSS hotfix page

Windows Vista and newer: De-select the System Reserved Partition from attempting a backup on the Advanced Options page.  Note: The SRP volume is not needed for any SIRIS virtualization or restore.  During the virtualization and restore process Datto installs the necessary boot information so as not to have junk boot data to attempt to virtualize/restore from.

Run through the Steps to Troubleshooting VSS Knowledge Base Article

Alternate path, provide crash consistent backups only with STC
  1. From the Datto SIRIS or SIRIS Lite web console click on Basic Options for the Protected System.


  1. On the Basic Options page set the Backup Engine to STC and click Apply.


Dale Shulmistra is a Business Continuity Specialist at Invenio IT, responsible for shaping the company’s technology initiatives -- selecting, designing, implementing & supporting business continuity solutions to bolster client operational efficiencies and eliminate downtime.