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Can't format SSD

idlerider

idlerider

macrumors newbie
Original poster
Dec 28, 2022
6
3
Dornoch
I have an 8TB pocket SSD but I can't format it. I've tried Disk Utility, TechTool Pro and Disk Warrior - they all say "formatting failed - can't read the last block." Any ideas about what I could use to zap the thing and format it?
 
Can you kindly provide the model and manufacturer of the SSD as well is on what Mac and version of macOS you are trying to format it?
 
Slartibart said:
Can you kindly provide the model and manufacturer of the SSD as well is on what Mac and version of macOS you are trying to format it?
Click to expand...
Mac is easy: 21.5" iMac late 2013, running OS X 10.14.6 Mojave. SSD drive less so: came from China, no manufacturer or model details shown on unit or packaging - just says 'Parameters - M2.'
 
it isn’t recognized when connected or is it? in case of the latter what does the system information report?

just a feeling here: maybe, just maybe this isn’t a 8TB ssd - while it reports like it, maybe it’s a fake… but before opening and looking inside, have you tried to connect it to a Windows or Linux system?
 
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It is recognised but says it's 'unreadable by this computer'. System report on the USB tree describes it as simply 'Product' and says:
UDisk:
Capacity: 8.39 TB (8,388,608,000,000 bytes)
Removable Media: No
BSD Name: disk4
Logical Unit: 0
Partition Map Type: Unknown
USB Interface: 0

I had thought of trying to format it from a Windows system - but it's hard to find anyone in this town who's still using one.
 
Try this. May help... or maybe not.
But try it... just to see.

Try using disk utility to format it to either "MS DOS" or "exFAT".
Does the format "go through" this way?

Is this a drive that came "pre-assembled", or was it an "m2 blade" that you put into an enclosure?
 
Tried both of those - same result. Fails with the message, "Unable to write to the last block of the device." ☹️

Drive came pre-assembled.
 
Would you be willing to bootcamp your iMac real quick just to slap Windows on since you are unable to find someone with a Windows PC and try to format it that way?
 
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I can’t find any known brand that offer an 8tb pocket SSD, the nearest I could find on Amazon UK that is a brand I’ve heard of is a Sabrent 4gb or a Crucial 4gb. As far as I can see no known brands sell such a thing. If you bought it from eBay or Amazon I’d request my money back. Otherwise you are out of luck
 
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Yep, the 'SSD's' (as described in listing) I found on Amazon look very dodgy.
£45 for 8tb.......🤣
 
Last edited:
idlerider said:
UDisk:
Capacity: 8.39 TB (8,388,608,000,000 bytes)
Removable Media: No
BSD Name: disk4
Click to expand...
Carefully, from Terminal:
-list available disks with
Code: 
diskutil list physical
to make sure that the 8.39 TB disk is still disk4
- format disk as GPT/ExFAT
Code: 
diskutil eraseDisk ExFAT ExFAT GPT disk4
or MBR/ExFAT
Code: 
diskutil eraseDisk ExFAT ExFAT MBR disk4

If it still fails, you can try with GParted Live https://gparted.org/livecd.php[/code]
 
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