I moved my files to T5 to boot from it but

[levmc]

As I restarted the iMac, I pressed the option button, but it went straight into my iMac as usual without giving an option to boot from T5.

What am I doing wrong?

my post from before: https://forums.macrumors.com/thread...-from-it.2336322/?post=31813506#post-31813506

 

[Juicy Box]

How did you “move“ your files?

If you just simply copied files to a hard drive you’re not gonna be able to boot from it.

Unless, you’re talking about you cloned your boot drive onto the external drive, that should work.

Or, if you installed a fresh OS on the external drive and migrated your files over to the new OS install, that should also work.

Let us know exactly how you moved your files.

 

[levmc]

I simply copied the files, using SuperDuper.
How do you clone the drive?

I selected "backup - all files" but it looks like I should have selected "Sandbox - shared users and applications"? Is that how you clone?

 

[Juicy Box]

I have never used SuperDuper, as I am a CCC user, so I will defer to someone with knowledge of SuperDuper.

 

[Fishrrman]

OP:
You are asking the same question in more than one thread.
This makes it difficult to reply.

Go to the startup disk preference pane.
Does it show the t5 as a bootable drive?

If it DOES NOT show up there, then something is wrong... it may have the files, but something that was required during the cloning process didn't "go through".
I suggest you erase the drive and start over.

If it DOES show up there, click the lock, enter your password, select the drive.
Then close system preferences and try rebooting WITHOUT the option key.

 

[levmc]

@Fishrrman

It works now, thank you.
I wonder why it didn't show up with the option key though.

 

[levmc]

It worked.
But now I got another iMac (2020) and I'm trying to do the same thing but it's not working.
I selected the drive but when I reboot, it shows a circle with an oblique line through it. What could be wrong?

 

[Fishrrman]

"I selected the drive but when I reboot, it shows a circle with an oblique line through it. What could be wrong?"

That means there could be something "wrong" with the OS, in that it may be incapable of booting the other Mac. Something is "missing". Perhaps a required file or resource.

Also, did you take steps (with the 2020) to over-ride "startup security" so that it is capable of booting from external drives? You must:
1. boot to the recovery partition (command-R)
2. open startup security
3. DISABLE startup security to allow booting from external drives
4. reboot the imac.
Now, try booting from the external drive again.

But again, if the OS on the external drive isn't "the right one", it STILL won't boot.

 

[levmc]

I did over-ride, but it showed that.
But I just booted from my older iMac, then migrated to the newer one. Problem solved. Thank you though.