New SSD restored from TM not detected internally — but is externally
First post here — hope someone can help.
I restored onto a 2TB Crucial SSD (CT2000MX500SSD1) from Time Machine and attempted to replace the existing 500 GB HDD with it, but on booting it up I get an alternating question mark folder icon with the Apple logo and a cross icon. I can successfully boot up the iMac with this new SSD via an external caddy (through the USB port) — but not internally.
I double-checked the internal connections to the SSD with the SATA data and SATA power cables but they seem nicely connected and I’m still getting the same issue. I then put the original 500GB HDD back to check I hadn’t damaged the cables / sockets but it booted up fine. I then replaced it back with the new SSD and still got the non-detection issue.
On a side note, not sure if this is related, but might be worth mentioning. When I tried to boot up externally with the original HDD via the caddy, the iMac wouldn’t detect it, but does detect the old HDD internally — and as mentioned, the caddy works fine booting up the iMac with the SSD.
Thanks for any help.
When I boot up with the Option key, it shows me the disk (SSD) and when I select it I get the flashing question mark folder > Apple icon > circle with line through icon — all on a rotation
These are the steps I took:
1. I removed the original 500GB Seagate HDD from my iMac and attempted to fit the SSD directly into the space (straight from the packaging without doing any preparative work) utilizing a new SATA cable and 2.5" to 3.5" mounting kit
2. I then rebooted and hoped to see the new SSD to perform a restore (tried holding down the Option key (for the startup manager) and again with Command+R (for recovery)) but couldn't see it
3. I opened the iMac again and double-checked the internal connections to the SSD with the SATA thermal sensor, data and power cables but they were nicely connected and I rebooted but still got the same issue
4. I took the SSD out of the iMac and used my 2018 MacBook Pro to erase and format it with the Mac OS Extended (Journaled) option
5. I then tried refitting it again in the iMac and rebooting. Still no joy
6. I tried again without going via the thermal sensor SATA cable but instead going directly with the iMac SATA cables — still no use.
7. I then decided to use an external caddy for the SSD to connect to the iMac via USB where I could successfully initiate an internet recovery to install MacOS and then do a TimeMachine restore
8. Whilst it was connected externally via the caddy it booted up okay and I could use the iMac as normal — but obviously I want to install it internally
9. I then opened up the iMac again and tried to install the SSD, rebooted and it failed again
10. I then put the original 500GB HDD back in to check I hadn’t accidentally damaged the cables / sockets but it booted up fine. I then swapped it back with the new SSD but again got the non-detection issue (flashing question mark folder > Apple icon > circle with line through icon — on a rotation)
Is this a good question?
Are you sure you formatted the SSD correctly? There are a few things you need to be careful here.
1 - Using GUID partition table
2 - Using the correct file system the system is expecting HFS+ (Sierra or older) or APFS High Sierra and higher)
3 - If the systems firmware got the needed update to run APFS drives.
So I'm suspecting you used a different system running APFS to setup your SSD drive and your Mac's firmware was not updated so the SSD work boot up as it doesn't understand how to.