This is a error triggered by insufficient disk space on the source volume (or a dedicated shadow storage area) when Acronis tries to create a consistent point-in-time snapshot.
If the error remains, collect Acronis System Report: acronis cyber protect b40901
Here’s a proper, structured guide for the error code B40901 . This is a error triggered by insufficient disk
Look for any writer with State: [8] Failed or Stable: No . If found, restart Volume Shadow Copy service and relevant services (SQL, Exchange, etc.). air-gapped physical server.
The Acronis Cyber Protect B40901 is a paradox solved. It offers the of a cloud-managed interface with the security of a local, air-gapped physical server.