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Partition external HD

Ramer

Ramer

macrumors newbie
Original poster
Nov 27, 2017
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(SOLVED) I purchased a Lacie Rugged USB-C 2 TB external HD to use with my 2017 MBP, I'm very new to the Mac world. I want to partition it and when I erase it the Partition button is greyed out. I'm on High Sierra. The format I used is MacOS Extended Journaled as it didn't give me the option to erase with the new AFS format. Am I doing something wrong or is it because the drive isn't an SSD? Any help would be appreciated.
 
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Ramer said:
I purchased a Lacie Rugged USB-C 2 TB external HD to use with my 2017 MBP, I'm very new to the Mac world. I want to partition it and when I erase it the Partition button is greyed out. I'm on High Sierra. The format I used is MacOS Extended Journaled as it didn't give me the option to erase with the new AFS format. Am I doing something wrong or is it because the drive isn't an SSD? Any help would be appreciated.
Click to expand...
Is your Mac in the GUID Partition Map Scheme? If not, that sometimes can be the problem. I had to format my internal drive because it was MBR and not GUID. Hope this helps. Cheers.
 
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Just to be safe, are you sure that you did not select the internal drive? You would see what you are seeing when you try that.

No data on the new external? Should be able to simply re-partition by selecting the top entry for the drive and click Partition.

Might want to open a Terminal window and past the results of the following command, to see what oddities might be going on with current format: diskutil list
 

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TekAdvice said:
Is your Mac is the GUID Partition Map Scheme? If not, that sometimes can be the problem. I had to format my internal drive because it was MBR and not GUID. Hope this helps. Cheers.
Click to expand...
Sorry, what do I check? All I know is that when I bought the MBP in November it updated to High Sierra. When I got the external hard drive I googled how to format it. Is there something I can check and start over?
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NoBoMac said:
Just to be safe, are you sure that you did not select the internal drive? You would see what you are seeing when you try that.

No data on the new external? Should be able to simply re-partition by selecting the top entry for the drive and click Partition.

Might want to open a Terminal window and past the results of the following command, to see what oddities might be going on with current format: diskutil list
Click to expand...
Definitely not the internal drive or it wouldn't be booting. What is the command to run in Terminal? Don't see it in your screen shot.
 

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You should be able to view what partition your drive is in by opening disk utility and selecting View. Then select show all devices. Select your external hard drive and see what the status is under the partition map heading. Hope this helps.
 
Thanks for everyone's help. I solved it (after really messing things up) by plugging it into my Windows machine and using Disk Management to remove the partition completely. When I plugged it back in my MBP I was able to erase it properly and then I could partition it!
[doublepost=1515208084][/doublepost](Hope this didn't post twice) Thanks for everyone's help. I managed to mess it even worse to the point that my MBP wouldn't even see it. So I plugged it into my Windows computer and using Disk Management I totally removed the partition. When I plugged it back into my MBP I was then able to erase and partition it properly!
 
My advice:
DON'T format the drive to APFS.
Use HFS+ instead, it's tried-and-true.

DO partition if you wish.
AFTER you erase it to HFS+.
 
Fishrrman said:
My advice:
DON'T format the drive to APFS.
Use HFS+ instead, it's tried-and-true.

DO partition if you wish.
AFTER you erase it to HFS+.
Click to expand...
Appreciate your advice, since it's not an SSD, APFS isn't an option anyway. I solved the issue last night though.
 
For the benefit of future readers, the disk came formatted with an FDisk partition table. It needed to be formatted with a GUID partition table. Disk Utility could have done that if the option was selected.
 
Good to know, but now I have a question. Are you referring to the internal boot drive which should not need any modifications or an external drive which could be either a platter or an SSD?
 
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