Troubleshooting STC failure occurred mid transfer. stcx.SnapshotError: Snapshot returned error code -87 for STC

Scope

This article describes that cause and possible solutions for the error STC failure occurred mid transfer. stcx.SnapshotError: Snapshot returned error code -87 for STC.

Cause

• The error code -87 is an official Microsoft System Error Code for "The parameter is incorrect."
• Third-party VSS-aware applications can block access to the Windows VSS writers, and cause this error.

Solution

• Make sure that any incompatible VSS-aware applications are not running on the protected server.
• The following backup services are specifically known by Datto to cause Error Code -87 to populate:
• Backup Agent
• Backup Extender
• Backup Updater

If these services are running on the production machine, disable them to prevent future conflicts.