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lyn-anne128
User level: Level 1 (4 points)

MacBook Pro cannot erase external hard drive with error -69877

Hi, Ive got a MacBook Pro which is about mid 2012 which Ive just upgraded to macOS Catalina 10.15.8

Im not in the position to replace it yet - we are retirees and not real wealthy so its beyond my reach at the moment and it still works for what I need it to do and is a lot happier with Catalina than with High Sierra.

I bought a 32TB hard drive cheap. This works. I've used it on the old Windows Vista machine we have. I wanted originally to take any windows data off the vista machine and save it onto the external drive. I was able to view it on the Windows Vista machine, I was able to format it exFAT on the vista machine and able to write to it, but It would not work on the Mac though.

No matter what I do, when I try to erase it I get an error -69877 Operation Failed - whether its using the Disk Utility or using Terminal.


I've looked at so many articles on what could be wrong, one of the suggestions was to erase it on a Windows machine by writing zeros end to end on it. So I tried that but I don't know if its made things worse.


Anyway when I look at the info on it this is what I get

Volume type : Uninitialised

BSD device node : disk2

Connection : USB

Device tree path : IODeviceTree:/PCI0@0/XHC1@14

Writable : No

Is case-sensitive : No

Volume capacity : 31,457,280,000,000

Available space (Purgeable + Free) : 0

Purgeable space : 0

Free space : 0

Used space : 31,457,280,000,000

Owners enabled : No

Is encrypted : No

Can be verified : No


Its been a very long time since I've been in the IT Industry.


so any help that I can get on this would be really useful.


Best wishes,

Lyn-Anne

Posted on Sep 20, 2026 9:07 PM

5 replies

HWTech
User level: Level 9 (78,350 points)

Sep 21, 2026 10:10 AM in response to lyn-anne128

Your screenshot here shows you are trying to erase your internal SSD!


I don't see the physical external drive in the Disk Utility screenshot.


I do see the physical external drive in your Terminal output....identified as "disk2". That is the item you want to erase. By default Disk Utility hides the physical drives from view, so you need to click "View" in Disk Utility and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility.


See the following Apple article (I'm providing an older version from the Wayback Machine since it actually has pictures which I think helps here):

https://web.archive.org/web/20250909095655/https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/mac



Is this 32TB drive a Hard Drive or an SSD? If it is an SSD, then it is a fake so don't trust it. A real 32TB SSD would cost thousands (or tens of thousands) of dollars. It is also still somewhat uncommon to see many 32TB Hard Drives. Most times people discover their drive is a fake when they try to erase them.


TheLittles
User level: Level 10 (211,627 points)

Sep 20, 2026 11:13 PM in response to lyn-anne128

"MacBook Pro cannot erase external hard drive with error -69877"

-------


Error -69877 on Hard Drive on macOS:

Indeed the full-storage capacity of this hard drive is irrational by today's market, numerically. Nonetheless, see what has been mentioned on these threads. Use this Google Search Query: "69825" site:discussions.apple.com

lyn-anne128 Author
User level: Level 1 (4 points)

Sep 20, 2026 11:08 PM in response to lyn-anne128

Hi. Yep. Pretty close. The diskutil list command shows 31.5tb which is an acceptable margin. It shows this same detail on Windows cmd.

There are lots of schisters(sp?) out there though. You’re right.

cheers.

kaz-k
User level: Level 9 (53,902 points)

Sep 20, 2026 9:54 PM in response to lyn-anne128

Hi,

I just wonder if your 31TB SSD is really "31TB" SSD. I got 20TB SSD was actually not that size SSD, it was scam.


Originally posted at discussions.apple.com/thread/256361607