Cloud storage is overused by backups of M365 (Teams, One Drive, etc) or Google Workspace (Google Drive). 

Backup storage size is several times bigger than the backed up data.


There are multiple causes why the C2C backups consume significantly more storage space than the data being backed up. Data handling works differently because of some peculiarities of the source storage itself.

1) Data deleted from the source is still included in the backup


Backup, recovery, or other operations with Microsoft 365 items fail with the following error:

.NET exception 'System.Net.WebException' has occurred: The underlying connection was closed: An unexpected error occurred on a send

This applies both to C2C backup and to local Agent for Microsoft 365.

Description of the issue:

  • You have created an encrypted group backup plan (for All Site Collections)
  • You are trying to browse/ recover the encrypted backups
  • A warning is shown "The backup you are browsing is encrypted. The search in encrypted backups is not supported."


Issue in the product.

Acronis Development Team is working on a fix.


C2C agent tries to apply a protection plan to O365 mailboxes, Sharepoint, etc.

Activity fails with:

A backup agent error: 'nothing is processed in protection applying'

Cause 1

The alert could appear if there are new resources but they weren't protected when applying the plan, for example when there are new items discovered in Microsoft 365.


Microsoft 365 Cloud-to-Cloud (C2C) backup or restore jobs are being executed slower than expected and take significant time to complete.


Cloud-to-Cloud backups are not that dependent on the total size of the backed up data (though this also has its role) but rather on the number of items that are being backed up.

Each separate item creates a separate request to Microsoft and depending on the number, throttling can be enabled on Microsoft side to reduce the load.