Can't find internal SSD

[hoody]

I'm up to me neck in it just lately. I have a new 1TB SSD that was fitted by a repair man with High Sierra. It's been going OK but today I booted up from the external spinner drive with Sierra installed via startup disc. I used an app that I can't get to work on the new drive, but when I went to reboot from the internal SSD, it wasn't there either in startup disc or disc utilities. I tried several times and ended up shutting down and then disconnected the external and hoped to start from there. No such luck; I got the start up sound and then nothing but a flashing question mark which I know means it can't find a drive. I've plugged the external drive back in and it's started up, but still not showing anything but the external drive in startup disc. I'm wondering if this has anything to do, either with an apple security update I put on this morning or that the new SSD internal will only show up on High Sierra.

 

[hoody]

I've found a part solution, although it's pretty much Heath Robinson. I must have been right that the new internal SSD wouldn't recognise Sierra I plugged the CCC backup from Sierra back in and started it. Once it was up and running I plugged in the CCC backup that I did a couple of days ago with High Sierra. I went to startup disc and there it was. I started from that and then chose the internal SSD from startup disc and it's now back to normal... whatever that is.
Anyway, I'm sure that some of you people have got a much better way of getting around this.

 

[MacInWin]

I booted up from the external spinner drive with Sierra installed via startup disc

Not sure what you mean by that, but if you changed the default startup disk to boot Sierra, that's probably why it didn't see the internal. The internal is probably formatted APFS, which Sierra does not recognize. The way to temporarily boot from an external drive is to hold down Option immediately after powering on and hold it until boot options appear on the screen. That way the default stays with the internal.

 

[Slydude]

Good thought, Jake. I missed that possibility the first time I read this thread.

 

[hoody]

I don't know what I'd do without you people, that worked perfectly. Thanks. One more question: I've got another external drive coming, a 1TB SSD this time and I'd like to get all the stuff from the external spinner drive mentioned above on to the new one. Is there a way I can transfer this?

 

[MacInWin]

If I remember correctly, you have Carbon Copy Cloner. That will do that for you quite nicely. Make the spinner the source and the new drive the target. You'll have to format the new one with the same format as the spinner, but once done, CCC will do nicely.

 

[hoody]

Why didn't I think of that. Thanks again.