External SSD not showing on desktop/disk util, however shows in System Info

[sfphoto]

Any thoughts on this issue?
Thanks for looking

HP500 SSD, HFS+ formatted external
Disk Utility does not see it nor
terminal:

diskutil unmountDisk /dev/disk1s2
Unmount failed for /dev/disk1s2

diskutil eraseDisk JHFS+ HP500 /dev/disk1s2
Could not find disk for /dev/disk1s2

(Also tried /dev/disk1s1)


Sys info
HP Portable SSD P500 500GB:

Product ID: 0x3282
Vendor ID: 0x090c (Silicon Motion, Inc. - Taiwan)
Version: 11.00
Serial Number: HASC33420202165
Speed: Up to 5 Gb/sec
Manufacturer: HP
Location ID: 0x14600000 / 25
Current Available (mA): 900
Current Required (mA): 304
Extra Operating Current (mA): 0
Media:
HP P500:
Capacity: 500.51 GB (500,510,490,624 bytes)
Removable Media: No
BSD Name: disk1
Logical Unit: 0
Partition Map Type: GPT (GUID Partition Table)
USB Interface: 0
Volumes:
EFI:
Capacity: 209.7 MB (209,715,200 bytes)
File System: MS-DOS FAT32
BSD Name: disk1s1
Content: EFI
Volume UUID: 85D67001-D93E-3687-A1C2-79D677F0C2E0
hp500:
Capacity: 500.17 GB (500,166,516,736 bytes)
File System: HFS+
BSD Name: disk1s2
Content: Apple_HFS
Volume UUID: D5F0905A-7EB4-3709-9EA1-9B6C261D5A32

 

[mdcmdcmdc]

I'm no expert, but maybe I can help get the discussion going.

How did you format it in the first place? Is this an older drive? The reason I ask is because I didn't think modern macOS versions allowed HFS+ formatted SSDs.

 

[chabig]

HFS+ is ok for an SSD, though APFS would be better.

Your Mac sees the drive at a low level. But it is having trouble recognizing, mounting, or parsing the partition map / file system on the drive.Try these things:

1. Make sure Finder is set to show external disks on the desktop. Are you sure it's not already showing in the Finder sidebar?

2. Disconnect and reconnect the drive.

3. Try a different cable, a different USB port.

4. Restart the Mac.

5. In Disk Utility, open the View menu and choose Show All Devices.

 

[sfphoto]

Thank you for your comments

@ mdmcdcmcd

1.How did you format it in the first place?
OS Sierra

2. Is this an older drive?
new last year, used once for backup, one of three, others are fine

@ chabig
1. Make sure Finder is set to show external disks on the desktop.
Done

1a. Are you sure it's not already showing in the Finder sidebar?
Is not

2. Disconnect and reconnect the drive.
Tried w/ several Macs, most have Sierra, newest has High Sierra

3. Try a different cable, a different USB port.
Tried other cables

4. Restart the Mac
see no. 2

5. In Disk Utility, open the View menu and choose Show All Devices
Done

 

[Nermal]

Can you please post the output of "diskutil list"? I'm not sure that it'll tell us anything that System Information didn't already, but it's worth a shot.

 

[bogdanw]

diskutil eraseDisk JHFS+ HP500 /dev/disk1s2
Could not find disk for /dev/disk1s2

(Also tried /dev/disk1s1)

The commands are not correct. It should be:

diskutil eraseDisk JHFS+ HP500 GPT /dev/disk1

Before easing, verify that HP500 is disk1.

diskutil list physical

If you use it for storage, I suggest making it MBR.

diskutil eraseDisk JHFS+ HP500 MBR /dev/disk1

 

[chabig]

Macs replaced MBR with GPT in 2011. I wouldn’t recommend it.

Which disk format?

APFS or HFS+? Which can Time Machine back up to? What about hard disks? Which format for use on PCs? And which are supported by Disk Utility now?

eclecticlight.co

Do you have any other computers (Mac or PC) that this works with? If so, try freshly formatting on one of them and then bring it back to this Mac.

 

[bogdanw]

Macs replaced MBR with GPT in 2011. I wouldn’t recommend it.

Formatting it as GPT creates an additional EFI MS-DOS FAT32 partition, unnecessary if the disk is used for storage.
It can also create confusions, as illustrated above where eraseDisk was directed at the EFI partition, instead of the disk.

Diskutil has two different commands
eraseDisk - Erase an existing disk, removing all volumes
eraseVolume - Erase an existing volume

 

[chabig]

Here is one of my external APFS SSDs. I see the EFI parition, but it's a meager 200MB, hardly significant.

 

[Fishrrman]

mdc wrote:
"The reason I ask is because I didn't think modern macOS versions allowed HFS+ formatted SSDs."

They absolutely DO allow you to format drives to HFS+.

In fact, on my m4 Mini, I have my INTERNAL drive partitioned.
First partition is APFS for the OS and "HD data" volume.

The "other three" partitions are formatted to HFS+.
Again, that's on an Apple INTERNAL SSD in an m-series Mac !

OP:
Can you take this drive to ANOTHER Mac?
If you connect it there, does it show up in disk utility and permit a re-format?

If not...
Can you take the drive to a Windows PC?
And try to re-format it THERE?
Does that work?

If so, bring it back to YOUR Mac, connect it, and see if disk utility will "see it" now.
If it does, NOW try a reformat to either HFS+ or APFS.

HFS+ should be:
"Mac OS extended, journaling enabled, GUID partition format". And DO NOT USE "case sensitive".

APFS should be:
APFS, GUID partition format, and again, DON'T USE "case sensitive".

 

[sunnyjohn2]

mdc wrote:
"The reason I ask is because I didn't think modern macOS versions allowed HFS+ formatted SSDs."

They absolutely DO allow you to format drives to HFS+.

In fact, on my m4 Mini, I have my INTERNAL drive partitioned.
First partition is APFS for the OS and "HD data" volume.

The "other three" partitions are formatted to HFS+.
Again, that's on an Apple INTERNAL SSD in an m-series Mac !

OP:
Can you take this drive to ANOTHER Mac?
If you connect it there, does it show up in disk utility and permit a re-format?

If not...
Can you take the drive to a Windows PC?
And try to re-format it THERE?
Does that work?

If so, bring it back to YOUR Mac, connect it, and see if disk utility will "see it" now.
If it does, NOW try a reformat to either HFS+ or APFS.

HFS+ should be:
"Mac OS extended, journaling enabled, GUID partition format". And DO NOT USE "case sensitive".

APFS should be:
APFS, GUID partition format, and again, DON'T USE "case sensitive".

Here's my two-pennyworth.
I'm running up-to-date Tahoe on my 2026 Mac Mini Silicon and had just this trouble. I googled it and was told to convert the EHD to HFS+, which I did. That solved the problem for the rogue EHD, but I have three others, all of which are APFS, and initially these would not show. However, once the first one appeared after converting, the other three did. It's as though once I got one to show, it allowed the other three to appear. I know that sounds daft, but that's what happened. All four now appear in both the Finder and the desktop, and, despite comments to the contrary, they all run perfectly well straight off the Mini.

For the record my EHJD's are: WD Elements 1TB 2023 APFS; WD Passport 1 TB 2024 APFS; Toshiba Portable Storage 2TB 2025 APFS (case sensitive); and a very old 'Coolbox' enclosure with a 500GB EHD inside - Mac OS extended (shows as USB) - probably at least six years old and still working!

Despite the above comment, my Toshiba does run as APFS Case Sensitive.

Hope that is useful

 

[sfphoto]

So... thanks to all.
Thinking I need to try with a PC at a friends home.
Oddly with Snow Leopard the HP external SSD shows in Disk Utility [app] but is grayed out and I can not repair or erase.
And Terminal can not find disk1
diskutil unmountDisk /dev/disk1
Unmount failed for /dev/disk1
diskutil list only shows disk0 (the internal)

 

[Fishrrman]

OP:

You may have done this already, but...
In disk utility...
... do you see a "view" menu up in the menu bar?

If you DO, go to it and choose "show all devices".
Doing this reveals the physical drives as well as the logical volumes.

If you want to completely erase a drive, you need to click on "the top line" for that device, and then use the erase command.

Also...
DON'T GIVE UP after the first try.
I've seen several instances where I tried to erase a drive and disk utility failed, returning a "couldn't unmount drive" alert.

BUT... if I simply repeated the process (went back and chose erase a second time), THEN the drive unmounted and everything went as intended.

EDIT to add one more thing...
I've had a couple of SSDs fail on me, and they just "went dark" -- never to be seen or revived again.
But... I've also read that sometimes an SSD can fail to some kind of "read only" mode. That is, you might be able to mount it on the desktop and copy files from it, but you can't write to it. This might be why disk utility can't "touch it". Just something to consider...

 

[sfphoto]

OP:

You may have done this already, but...
In disk utility...
... do you see a "view" menu up in the menu bar?

If you DO, go to it and choose "show all devices".
Doing this reveals the physical drives as well as the logical volumes.

If you want to completely erase a drive, you need to click on "the top line" for that device, and then use the erase command.

Also...
DON'T GIVE UP after the first try.
I've seen several instances where I tried to erase a drive and disk utility failed, returning a "couldn't unmount drive" alert.

BUT... if I simply repeated the process (went back and chose erase a second time), THEN the drive unmounted and everything went as intended.

EDIT to add one more thing...
I've had a couple of SSDs fail on me, and they just "went dark" -- never to be seen or revived again.
But... I've also read that sometimes an SSD can fail to some kind of "read only" mode. That is, you might be able to mount it on the desktop and copy files from it, but you can't write to it. This might be why disk utility can't "touch it". Just something to consider...

"do you see a "view" menu up in the menu bar?"
Thank you, Yes to 'all devices' and such is checked to no avail. Thinking a PC is the next thing to try.

 

[sfphoto]

Can you please post the output of "diskutil list"? I'm not sure that it'll tell us anything that System Information didn't already, but it's worth a shot.

Disk1 does not appear on the list, only disk0 (the internal)

 

[AlaskaMoose]

I would like to mention something that may or not be an answer to your troubles about your Mac not recognizing the external hard drive, but here it goes, just in case: a year or so ago my 1019-2020 iMac would fail to mount a hard drive where I had stored a great number of photos. Later I realized that I had forgotten a an antivirus/malware app was set to scan for malicious of all external devices (CD's, DVD's, hard drives, SSD's and so on). Since I had so much data in the hard drive, the anti-virus app was taking quite a long time to scan the entire hard drive. Even scanning all the data on my iMac's internal hard drive would take over an hour . After disabling the scanning of external devices, the problem was solved. 🙂

 

[sfphoto]

Thanks everyone for your responses. My neighbor was not successful using his PC either, even using the command line. So... bad interface or other issue w/ the drive.

 

[Fishrrman]

OP wrote:
"My neighbor was not successful using his PC either, even using the command line. So... bad interface or other issue w/ the drive."

My GUESS is that the drive has failed into some kind of "read only" mode.
If there is any data you value on it, copy that data OFF OF IT.
Then put the drive into the closet and leave it there...

 

[blufrog]

Did you remove the drive and try and access it via native cable (e.g. SATA)? It could be the enclosure is busted but the drive is accessible.

 

[sfphoto]

@blufrog - It is not a 2.5in external but smaller & likely an MVNe blade as is common for compact externals.

@Fishrrman - Can not access the drive to copy. Fortunately it is a second backup (I generally make two every couple of months) AND still under warranty so am returning to HP.