I know I can boot from a Firewire clone, but can I boot from a USB clone on a 27" early 2009 iMac (iMac11,1)? It shows up as an optional boot drive, but the iMac always boots from the internal instead. Running El Capitan on both.
Yes, although slow that Mac will startup from a USB drive.
You need to change the Startup Disk Preference while started up from the Internal HDD.
Optionally, you can hold the Alt (option) key at startup and select whichever drive from the Startup Manager.
I would think that yes, you can boot from a USB drive. But being that vintage Mac the USB drives would be driven through a USB-2 port and rather slow (even if the drive is a USB-3, it will only run as fast as the port allows). I have the same situation with my mid-2010 i-Mac. I make bootable clones as a secondary back-up option and find that they do boot, but are almost painfully slow.
Personally, I use the 'hold down the option key" method as it leaves the internal HD as the normal boot drive once the back up clone has been tested and verified. You may have other goals and reasons for booting from the USB drive. BTW, it takes about 4 hours to make the bootable clone with my approx 280 GB of data at USB-2 speeds.
My USB-2 drive has multiple partitions, all formatted correctly, but only one is bootable. It is strictly a backup for emergencies, but after I do a SuperDuper! clone, I always test that it will boot. When I do a restart, either with Preferences changed or using the Option key, the clone partition shows up labelled as "EFI Boot". Using Disk Utilities all the partitions have the correct names. So, I'm not sure that the one USB drive that does show up is really the clone or maybe one of the other partitions that won't boot. Yes, USB-2 is slow and it took about 8 hours for my backup. That's okay since it's only for an emergency restore if I need it. But at this point, I'm not sure why my iMac always boots with the internal drive. I've also got a Firewire clone that does boot up correctly and it also is labelled as an EFI Boot device when I boot with the option key. Guess I'll try to clone my old Snow Leopard partition to the USB drive and see what happens with 2 bootable partitions. The SL partition is MUCHO smaller so should go much faster. Any other thoughts are welcome!
One other thing--when I do use System Preferences to specify the clone as the startup drive, it is correctly labelled and listed as OS X, 10,11.3, same as the internal drive. It's only when I use the Option key on restart that the EFI Boot label shows up.
Guess I'm not responding correctly, but whatever..........
My Fire Wire drive is about 10 years old and is therefore somewhat suspect. And, I'm hoping one of these days to upgrade this old iMac which will then use USB3. My new USB drive is a 3TB USB3 drive. In addition, my 6 year old Time Capsule has decided that it has been transmitting with too much power, apparently, and Wi-Fi in much of the house is at a crawl. While the HD is still working well--who knows? Therefore, the new USB drive would also take the place of the TC's HD.
All the partitions have unique names. However, apparently something must not have been successful with the SuperDuper! backup. I did clone my internal SL partition to another of the USB drive's partitions. Using the Option key boot, that clone did show up correctly, along with the EFI Boot drive. The SL clone does boot correctly! With some additional scouting around, I did an INFO in the finder to the various partitions. I noticed that the clone that doesn't boot did not have the OS X Version number listed as do the other bootable partitions. So that's leading me to conclude that the 8 hour clone job just didn't complete correctly.
Thanks for all the suggestions, and the original question has been answered--the late 2009 iMac does boot from a USB drive.
Yes you can do that. Have you changed the startup disk selected in System Preferences -> Startup Disk?
You might want to try making the USB bootable clone on an unpartioned, dedicated external HD. BTW, why do you want both a bootable Fire Wire clone and a bootable USB clone?
Give them different names or add a something to the names like 1 and 2, so that you can easily distinguish one from the other.
Will a late 2009 27" iMac boot from a USB drive?
