Backup fails with the following error:
The activity has failed because the machine has been shut down unexpectedly
Such error occurs if the system crashed, rebooted or was shut off unexpectedly during backup process.
1. Check for possible external causes of reboot: power failures, user intervention, hardware issues.
2. Check system logs to investigate the root cause of the crash:
- Open Windows event viewer: Start -> in Search, type eventvwr.exe and press Enter.
- Navigate to Windows Logs -> System. Click Filter Current Log. In Includes/Excludes Event IDs specify 6008. Check the log for other events that occurred around the same time as the unexpected shutdown
See also Acronis Software: Troubleshooting Operating System Crashes