1. You back up a Windows machine,
2. Backup finishes with warning "Volume Tracker has failed to freeze checkpoint. A device attached to the system is not functioning"
Volume Tracker is a change block tracking driver that accelerates backup process: changes to the disk or database content are continuously tracked at the block level. This error occurs when Volume Tracker cannot get the necessary data from Microsoft Shadow Copy Provider.
If Volume Tracker was unable to process changes, then you will receive a warning and changes since last backup will be calculated by Agent instead.
1. Check whether there are third party VSS providers installed on the affected agent machine:
Using Command Prompt:
- Launch Command Prompt as Administrator: Start -> in Search, type cmd -> right-click cmd.exe and select Run as administrator.
- Type the following command: vssadmin list providers
- Output will contain list of VSS providers and their IDs
Using Windows Registry:
- Go to Start -> Run -> type regedit
- Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Providers and check the list of available VSS providers on the machine
If you confirmed that there are third party VSS providers besides Microsoft VSS Provider, select Use Microsoft Software Shadow Copy provider option in backup plan options.
2. Verify status of VSS components using Acronis VSS Doctor.
If you do not find any third-party providers or suggested solution does not help, collect Acronis VSS Doctor output and system information from affected agent machine and contact Acronis Customer Central.
- For Acronis Backup 12.5 see Acronis Backup 12.5: Collecting System Information
- For Acronis Backup Cloud see Acronis Backup Cloud: Collecting System Report
You can disable Changed Block Tracking in the backup options as temporary workaround until the issue is resolved. Please note that it can slow down the backup.