
Try disabling write caching for the USB drive to solve the issue
This article applies to:
Symptoms
- You are trying to backup to a USB drive;
- The backup operation fails with the following error messages:
Device is not ready
Failed to create volume snapshot
View sample log
Cause
USB drive write caching is enabled (Optimize for performance). When write caching is enabled, the USB drive may fail to initialize in time when Acronis product accesses it. As a result, the product will error out with Device is not ready.
Solution
Disable write caching for the USB drive:
- Right-click the My Computer icon and then click Manage;
- Click the Device Manager icon;
- Click the plus (+) sign next to Disk Drives;
- Double-click the USB hard drive string:

- Click the Policies button then click the Optimize for quick removal radio-button and click OK:

More information
See also Multiple "Failed to read from sector..." Error Messages During Partition Analysis or Backup.
If the issue persists, please contact Acronis Customer Central with a reference to this article.