SIRIS, ALTO, and NAS: STC Failure Occurred Mid Transfer (6, 'closehandle', 'the handle is invalid.')



This article describes the cause and possible solution for the error: STC Failure Occurred Mid Transfer (6, 'closehandle', 'the handle is invalid.')


This error typically appears when there is an issue with the ShadowSnap agent communications. This is a Python error that could signify a corrupted ShadowSnap install.


  1. Ensure that there are antivirus exceptions for the StorageCraft directories and services.
  2. Force a differential merge from the Advanced section under the Configure Agent Settings page.
  3. If the issue persists, reinstall the ShadowSnap agent by following the steps described in Using PsExec To Install The ShadowSnap Software.
  4. If backups continue to be unsuccessful, contact Datto Technical Support for further assistance.

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