SDErrorDomain error 104 when trying to run Ventura on external SSD

[KSM5000]

I have a 2017 iMac with Intel processor that is running incredibly slowly. I read that I can run macOS on an external SSD to, hopefully, speed things up. I bought a Crucial X9 Pro for Mac 1TB SSD. I formatted it to APFS with the GUID partition map, downloaded Ventura from the App Store and installed it on the external drive. In system preferences I have selected the external drive as the startup disk but when I try to restart I get error 104. Any suggestions?

Thanks.

 

[Bigwaff]

Mac Unable to Set Startup Disk (SDErrorDomain error 104/108)

You are asked to select a startup disk to install the macOS but it says 'Unable to set startup disk' and can't bypass to continue the installation. Reading this post to know how to fix this error.

iboysoft.com

 

[KSM5000]

Thanks. I'm familiar with the post. I'm not sure that it provides and answer to my problem.

 

[Fishrrman]

Just a few thoughts.

You didn't tell us WHICH OS is on the iMac's internal drive.

I realize you have Ventura installed, but have you considered wiping the X9 clean, and then try a different OS instead?

I'm thinking, "Monterey".

If nothing else works...
... from a powered-off status, can you successfully boot by holding down the option key to invoke the startup manager?

 

[KSM5000]

Just a few thoughts.

You didn't tell us WHICH OS is on the iMac's internal drive.

I realize you have Ventura installed, but have you considered wiping the X9 clean, and then try a different OS instead?

I'm thinking, "Monterey".

If nothing else works...
... from a powered-off status, can you successfully boot by holding down the option key to invoke the startup manager?

Thanks for this. To clarify, Ventura is installed on the internal drive and I can always successfully boot into that drive. I have wiped and installed Ventura on the external drive a few times trying both APFS and Mac OS Extended (Journaled) as files systems. Monterey is a good suggestion. I'll give it a try.

 

[KSM5000]

As a follow up... I used terminal to create a bootable disk to install Ventura onto the external SSD. Following that installation the SSD does not appear anywhere as a startup option, whether in system settings/ startup disk or in the startup manager. I never get to the point of setting up as a new computer.
2017 iMac 2.5", running Ventura 13.6.4, 2.3 GHz Dual-Core Intel Core i5 processor, no evidence of a T2 security chip.
Apparently Monterey is not an option if I'm running Ventura already. It's all making me a bit crazy. Thanks for any support.

 

[KSM5000]

Further follow up. I just had complete success using a G Drive Mobile drive I had lying around. - that is, installing and running Ventura on an external drive. Unfortunately it's not SSD tech so won't solve my speed issues, but seems to prove I was doing things correctly and the Crucial drive is the issue. I've reached out to Crucial.

 

[KSM5000]

One final follow up. After a couple communications with Crucial support, I returned the X9 Pro and picked up a Samsung T7 (that was actually $30 cheaper). Formatted it and installed Ventura without a hitch (although it took a while). The iMac is now dramatically faster. Exactly the result I was looking for.

 

[greyeyezz]

What you can do is use carbon copy cloner to do a standard backup(files, apps, settings) to your T7, then run the ventura installer right onto the T7 and you will boot into a perfectly cloned, identical, freshly installed OS as your internal.

 

[aimunna]

One final follow up. After a couple communications with Crucial support, I returned the X9 Pro and picked up a Samsung T7 (that was actually $30 cheaper). Formatted it and installed Ventura without a hitch (although it took a while). The iMac is now dramatically faster. Exactly the result I was looking for.

Hi, I'm having exactly similar issues with a SANDISK Portable - USB 3.2 Gen 2 1TB drive. I tried fresh installing Ventura, it'll download all files and take quite a bit of time installing but near to the end will fail. Then I tried cloning the onboard HDD into the SSD which seems to be completed without an issue, now when I try to set the SSD as the boot Drive, it'll fail with the Error 104. I think I'll not be able to return the SSD, is there any list of drives which will be compatible for upgrading iMac?