How hard is it to make a bootable external?

[Panicof1907]

All I wanted was to make a copy of my content on my super old and slow internal HDD, so it's on a fast external and just boot from that. Unfortunately, despite picking up a T7 tonight, I can not for the life of me format it to APFS.

I also can't use the disk utility to restore the internal HDD to the external like every other tutorial declares is easy as cake.

After more troubleshooting, I've read rumours that Apple now has deliberately disalowed the ability to clone the internal HDD to a bootable external.

I am just shaking my head here.

I picked up a 2 TB external to match the 2 TB internal and never before do I recall this being so hard to do.

And I missing some new trick here?

 

[Bigwaff]

What year and model iMac? What version of macOS installed?

 

[Panicof1907]

iMac 5K 27" 2017

Ventura 13.2.1

 

[gilby101]

And I missing some new trick here?

No new tricks.
Format T7: Disk Utility, View > Shows All Devices, Select T7 and Erase button. Use format APFS and scheme GUID Partition Map.
Clone your system: Use Carbon Copy Cloner or SuperDuper! (both have free trial).
Booting: Either in System Settings set the boot disk to the T7 or hold Option key when booting to get choice of boot disk.

 

[Fishrrman]

2017 iMac?
Plug the t7 into the USBc port for fastest speeds.

You need to REMOVE any Samsung software on the drive.
Like gilby says above use disk utiity to erase entire drive to APFS, GUID partition format.

I'd recommend SuperDuper for the cloning job.
Free to download, VERY easy for a first-time user to understand.

When done, go to the startup disk settings pane, set the t7 to be the startup drive.
Then restart...

 

[FreakinEurekan]

iMac 5K 27" 2017

Ventura 13.2.1

Also - unless that was a typo - update to 13.7.1

 

[pshufd]

It should be straightforward though I've done this a few dozen times so it seems pretty easy. I last did this with a 2015 iMac which is sitting on a table right now. I've even created an external bootable from my 2015 MacBook Pro to run on my 2015 iMac 27 - this was when I went to look at the system to consider buying it.

Hopefully the instructions in earlier replies helps you to get it done.

 

[Panicof1907]

Thanks guys. I was able to format to the correct format 'APFS' by changing some other options in disc utility.

I am now using SuperDuper for the first time. I had first heard about it and remember lots of positive reviews about it way back around the time Steve Jobs passed away. Didn't think I'd ever have a need to use it though.

Right now it is over half-way done copying. Though I suppose I should have used the USB-C port instead of the regular looking USB ports. The problem is that I have an additional monitor on the left and right of my main iMac, and both are using the only two USB-C ports IIRC.

Maybe I should see if it's possible to buy a USB-C splitter to use multiple devices at the same time through there? Though even if it's possible that may degrade speed/signal to be not worth it?

It's been a little bit of a learning experience so far here. I"ll be happy I guess if the copying manages to finish without more errors. Rough estimation is maybe another two hours or so.

 

[Fishrrman]

I'd leave the t7 connected to the USBc port "by itself".
If you're thinking of "a hub", plug that into the other port.

If you're going to buy a hub, be sure to buy a POWERED one (it will have it's own power supply adapter). This way you don't risk overloading a port with devices that want "too much bus power".

 

[gilby101]

Though I suppose I should have used the USB-C port instead of the regular looking USB ports.

The USB-C ports would operate at 10 Gbit/s. The USB-A at 5 Gbit/s because, on an iMac, they are only USB 3.0. But, in practice, your transfer speed would be limited by the internal HDD, not the USB.

In the long run, you should be thinking about using one of the USB-C ports with a suitable powered hub for the two monitors. As Fishrrman describes.

 

[Panicof1907]

Thanks all. This week I will try to order a usb-c powered-hub for the thunderbolt port(s) on the back of this iMac.

As for an update, after many, many, many hours last night, finally the copy completed. Then as expected by my fears, I got an error so it was all for nothing. I tracked down the error and others had said it was due to either the iMac going to sleep during the copy, or a process took too long during the copy which made the final completion invalid.

I switched to the thunderbolt port, and re-started the copying again this morning with SuperDuper. Keeping my fingers crossed but not holding my breath.

Definitely seems faster though now. I also emptied the trash-can to free up over 100 gigs of stuff that won't be copied now. Fun fact, I had guessed (wrongly) that trashcan stuff would be one of the file-characteristics that would be ignored.

I really miss the days when this was simple ("it just works"). You just let time-maching copy to the external... and then you could boot-up from the same external. Grrrr.

 

[Panicof1907]

Update!

So, we finally have success.

The last clone went through (phew). And I did a boot-test from it. My internal system fans went crazy for a short while after the first bootup, but now they slowed down again.

Definite major speed improvement on boot-time. Wish things were a little faster still, but I won't complain much.

I may switch the SSD from the Thunderbolt back to the regular USB slot so I can free up my other monitor again, but I'm not sure if doing this will hamper speed on the SSD or be negligible for ordinary use and gaming, now that the major file-copying is done with.

Will be watching closely throughout next week.