Physically connecting a Fusion drive created by OS X Mavericks or later with a Mac using OS X Mountain Lion v10.8.4 is not recommended. Activities that create sustained, intensive drive activity (such as video editing) may result in the Fusion drive becoming unreadable.
- To avoid this, update your Mountain Lion computer to OS X v10.8.5 or later before connecting your Mavericks-based Fusion drive.
- If your Fusion drive is unreadable as a result of connecting it to an older OS version, reformat the drive using Disk Utility. Then, install OS X Mavericks and restore from backup.
This symptom does not occur when connecting to a Fusion drive using File Sharing, instead of target disk mode or other physical connection methods.