Can’t Boot From Your Clone Backup? Make Sure It’s Direct Connected

This may seem like an obvious tip, but it cost me several minutes of frustration this morning so I thought I’d share my experiences. I make a point to create nightly clone backups of my computer to a direct connected USB drive. I’ve discussed this process when explaining my backup system. In short, I like having an exact duplicate of my system so in the event of a hard drive failure I’m able to resume work and recover my data more quickly. My application of choice is Carbon Copy Cloner, though SuperDuper! is great too.

No backup is fool proof. Sometimes hard drives die or files become corrupted. Therefore every now and then (usually once every month or so) I make a point to boot my Mac from that clone drive just to confirm that the drive is bootable and everything appears to be working. There’s nothing worse than needing your backup only to find it’s no good.

Recently, my Mac refused to boot from the clone. My clone disk appeared as a selectable Startup Disk in System Preferences, but even after trying the troubleshooting steps documented by Carbon Copy Cloner, the drive wouldn’t boot. Fearing something may be wrong with my backup drive, I started to think what had changed since the last time I tested the clone. I recently upgraded my USB hub to a 3.0 hub. The CCC knowledge base seems to indicate that USB 3.0 drives could have trouble booting with certain computers. 

In what should have been an obvious answer all along, I directly plugged the clone Hard Drive (A Seagate 1TB USB 2.0 Hard Drive) into my computer restarted and tried again. It booted up immediately (or as quickly as a USB 2.0 Hard drive can be expected to boot.)

Lesson learned. When booting from a USB drive, you should have it direct connected to your machine, not through various hubs. But more importantly, don’t forget to regularly test those backups.