External drive doesn't show up on orignal mac it was created on, but does work on newer Mac.

Question

External drive doesn't show up on orignal mac it was created on, but does work on newer Mac.

Hi,

I had major problems with my i7 Imac internal, so I booted up with an external that I was using to start up with on my i5 Imac It was great and stable. I screen shared with it everyday for a few years, but it doesn't show up anymore on the i5. They are both running the same OS High Sierra. Could something have upgraded just being used on the newer Mac for it to not be recognized by the old Mac anymore?I don't remember clicking anything unless it was a security update maybe? It appears that it shows up in terminal before startup (Cmd-R. utilities), but I'm not sure if it's that disk. I see a 2nd disk that shows up in terminal on the old machine, but it's greyed out, so I can't run disk first aid on it. It also doesn't show up as an option to use as a startup disk.

Is it possible to fix it so that it will work on the i5 without erasing it?

Thanks,

Frank

iMac 27″ 5K, macOS 10.13

Posted on Aug 22, 2020 10:58 PM

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Answer 1

Top-ranking reply

TheLittles

Level 10

196,467 points

Aug 22, 2020 11:13 PM in response to Macs Are War Horses

Macs Are War Horses Said:

"External drive doesn't show up on orignal mac it was created on, but does work on newer Mac.: [...]It appears that it shows up in terminal before startup (Cmd-R. utilities), but I'm not sure if it's that disk. I see a 2nd disk that shows up in terminal on the old machine, but it's greyed out, so I can't run disk first aid on it. It also doesn't show up as an option to use as a startup disk. Is it possible to fix it so that it will work on the i5 without erasing it?"

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Try the Following:

Mount the Drive in Recovery Mode:

Boot into Recovery Mode, click the drive, and tap "Mount".

Uninstall Security Software:

Any Security Software installed? If so, u install it. Use the uninstaller to do so. Contact the developer for the correct method of removal. Its privacy settings are probably disallowing it to be accessed.

Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM.

Boot with the Drive Plugged in:

Shut down the Mac. Unplug the drive for thirty seconds, then plug it biack in, and then boot up. See if it is seen

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Answer 2

Aug 23, 2020 3:05 PM in response to TheLittles

Hi TheLittles,

Thank You for your quick response! It appears on the desktop as a folder. This is after I did disk utilities on the main drive. I can access things that are locked. Then I did a command - R again thinking it might recognize it. The disk is shown but greyed.

I plan to try all of your ideas starting with zapping the Pram. i'll try them during the course of the night and I'll get back to you.

Thanks,

Frank

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Answer 3

TheLittles

Level 10

196,467 points

Aug 23, 2020 4:56 PM in response to Macs Are War Horses

Macs Are War Horses Said:

"I plan to try all of your ideas starting with zapping the Pram. i'll try them during the course of the night and I'll get back to you."

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You are welcome.

I think that mounting it in Recovery Mode would do the trick.

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Answer 4

Aug 23, 2020 8:46 PM in response to TheLittles

Hi TheLittles,

Thank You again for your help. Couldn't get it to mount as a startup though. I have it going through disk first aid in my i7. Hopefully, this will help fix any issues when I try it in my i5 again. It's getting late where I live. Not sure if I will be able to set that back up on my i5.

I'll keep you posted!

Frank

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Answer 5

TheLittles

Level 10

196,467 points

Aug 23, 2020 9:01 PM in response to Macs Are War Horses

Macs Are War Horses Said:

"Hi TheLittles, Thank You again for your help. Couldn't get it to mount as a startup though. I have it going through disk first aid in my i7. Hopefully, this will help fix any issues when I try it in my i5 again. It's getting late where I live. Not sure if I will be able to set that back up on my i5.I'll keep you posted! Frank"

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You are welcome.

IMPORTANT: Place it on a laptop cooler so it doesn't overheat.

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Answer 6

Aug 24, 2020 6:19 PM in response to TheLittles

Hi TheLittles,

It's puzzling to me as it works great in my i7! Well, I am working on getting back my data on my i7, so I'll have to table that for a while. I've finally bought the paid version of recovery software and a hard drive to save it on.

I've got going now. It takes like 6 hrs. to complete. I have another scan I will do tomorrow. After that it's back to trying to get my i5 to recognize this external.

I'll keep you posted, but give me a few days and thanks again!

Frank

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Answer 7

TheLittles

Level 10

196,467 points

Aug 24, 2020 8:13 PM in response to Macs Are War Horses

Macs Are War Horses Said:

"Hi TheLittles, It's puzzling to me as it works great in my i7!: [...]I have another scan I will do tomorrow. After that it's back to trying to get my i5 to recognize this external[...]."

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You are most welcome.

Keep it on a laptop cooler - don't forget that - if you have one - as it can get hot, just laying about.

Let us know how it works out.

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External drive doesn't show up on orignal mac it was created on, but does work on newer Mac.

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