Hi. I downloaded a .dmg from a reputable site but it wouldn't mount. My external drives also won't mount.

Is this a big in the latest macOS Monterey? If you had the same problem, how did you fix it?

Thank you. Stay safe.

God bless, Revelation 21:4

P.S. Mac is a Late 2015 iMac w/ 24GB RAM, 2TB factory installed hard drive only (non-Fusion drive. I plan to upgrade it to a 1TB SSD)

I'm looking at 4 external drives and a NAS in my Finder right now and all of my downloads are stored and installed from one of them, its not a bug.

There are huge problems with Monterey and external SSDs - especially 4TB.

I had to revert back to big sur which cleared up all problems. I have a 2019 iMac i9 booting from a 4tb Samsung EVO 860 in oyen enclosure.

Monterey 12.1 hangs formatting these external USB drives and installing to them. Also it cannot mount many external drives. A lot of issues with G drives. Some have had some success using a USB 2.0 cable - that is too slow and there is no guarantee that your data integrity is good. USB3C and USB3A don't make a difference.

Western Digital has announced there is a compatibility issue

This is a big problem - not sure why it has not been broadly recognized. Search web and you will find lots of people have this issue. Unstable mass storage is the death of a computer system. It is clearly the OS. Trying to decide if i need to revert my MBP2019. It runs on Apple internal 2TB SSD and appears to be working fine.
It couldn't format the EVO either or install to it.

Strongly suggest you do not upgrade.

Maybe their SSDs have an issue but their HDDs definitely do not. My Time Machine drive is an 8TB WD Easy Store, my Storage drive is a 4TB MyBook, my USB-C drive enclosure has a 1TB OWC SSD holding all my audio projects from Logic/Cubase/Ableton/etc, and my drive full of sample libraries is a 1TB EVO I picked up on Black Friday last year. Not a single problem formatting or writing or reading to any of them on Monterey. My whole recording studio and Mac in general would be dead in the water if there was an issue with any of them.

Alvin777 said:

Hi. I downloaded a .dmg from a reputable site but it wouldn't mount. My external drives also won't mount.

Is this a big in the latest macOS Monterey? If you had the same problem, how did you fix it?

Thank you. Stay safe.

God bless, Revelation 21:4

P.S. Mac is a Late 2015 iMac w/ 24GB RAM, 2TB factory installed hard drive only (non-Fusion drive. I plan to upgrade it to a 1TB SSD)

Click to expand...

In finder prefs,

and system prefs, security and privacy tab just a shot in the dark and upgrade to SSD

I updated to the latest Monterey, 12.2 but it's still not mounting .dmg images and external storages (flash drive, hard disk, etc.). This is after resetting the SMC and PRAM as well.

I was wondering if there's a Terminal command to force mount everything? Perhaps, while this bug is not fixed yet, I can create a script in Automator so it force mounts it using that Terminal command every boot up?

I'll try using Onyx app as well.

Thank you.

Alvin777 said:

I updated to the latest Monterey, 12.2 but it's still not mounting .dmg images and external storages (flash drive, hard disk, etc.). This is after resetting the SMC and PRAM as well.

I was wondering if there's a Terminal command to force mount everything? Perhaps, while this bug is not fixed yet, I can create a script in Automator so it force mounts it using that Terminal command every boot up?

I'll try using Onyx app as well.

Thank you.

Click to expand...

No luck with Onyx.

Alvin777 said:

No luck with Onyx.

when you plug in the flash drive can you see it in disk utility?

Hi. Sadly no. It even doesn't mount .dmg images when I double click them.

What could be the fix?

Alvin777 said:

Hi. Sadly no. It even doesn't mount .dmg images when I double click them.

What could be the fix?

That is weird. No there isn't any bug regarding that I think. Here try this. Go to System Information app. Like hold option key and click the Apple logo on top left. It should show System Information. Click and open it. Go to the USB tab.

Plug in your USB etc. Then do a refresh so command+R

Does it show at all? If the Mac detects the USB it'll show there. Even if it's not mountable.

Last resort is to try going to recovery. And disk utility. And then plugging in your HDD or USB there. See if it mounts or even shows there

Alvin777 said:

Hi. Sadly no. It even doesn't mount .dmg images when I double click them.

What could be the fix?

can you do a get info on the .dmg?

EssentialGadget said:

There are huge problems with Monterey and external SSDs - especially 4TB.

Monterey 12.1 hangs formatting these external USB drives and installing to them.

Western Digital has announced there is a compatibility issue

I have a few WD 4TB NVMEs they all out mount fine in Thunderbolt 3 enclosures on the M1 Pro (Monterey 12.0)
So not sure if this more of an issue with 12.1?

I see the mounting issue is with some usb 3.1 gen 2 enclosures and I do have a 3rd party one that won't mount when directly connected to the M1 Pro. However, it will mount when connected to a thunderbolt dock that is connected to the M1 Pro.

I've experienced the formatting issue, it will format a drive but it takes forever, like over a minute.
Not sure what's going on there.

Where has Western Digital announced a compatibility issue? A google search yielded zero results

I've noticed oddities with Monterey and the systems with M1 chips. In your case, as you system is not with an M1 chip, then it may be as others have noted, quirks and issues with the OS. This reminds me of long ago compatibility issues with Windows while Apple computers simply were true plug and play.

Just for your interest - running a hub off my system via thunderbolt and attached are two external drives (one USB 3.0and the other tb) along with a USB cable for audio out to a pair of speakers. The drives have worked consistently (one being Time Machine - Samsung T5) and only the audio on rare occasions was a problem. When I plugged the drives directly into my computer, they also worked fine (as that is where they originally resided before the hub).

I share this so you know others also are sensitive to the issues of Monterey and you are not alone with some challenges (mine only being the usb audio out).

AL2TEACH said:

can you do a get info on the .dmg?

Hi, sure. Thanks in advance for helping out.

Alvin777 said:

Hi, sure. Thanks in advance for helping out.

In the open with, what app do you have to open it. It might not make any difference but I downloaded the same app (I had this before and trashed it, lol) did a get info and it opens with DiskimageMounter (default).

AL2TEACH said:

In the open with, what app do you have to open it. It might not make any difference but I downloaded the same app (I had this before and trashed it, lol) did a get info and it opens with DiskimageMounter (default).

Hi, thanks. I'll most likely reinstall macOS, I've wanted to do that for a long time and delete a lot of files, that aren't that important or have served their purpose (lots of photos that has nothing to do with current goals for example). Thanks again.

Alvin777 said:

Hi, thanks. I'll most likely reinstall macOS,

wow, wish I had the patience to do that one, lol.

After updating to 12.2:

- My printer with usb connection no longer connects, with any connection (multiple hubs tried) to my mac!
- Currently, a usb flash disk, which works well with other computers, no longer connects to my mac.

I do not know what they have done, but there is a problem.

I hope the next update (the last one didn't fix it) and I've done SMC, PRAM resets, tested the USB stuff with another computer (they're fine), checked if the hardware is not working using Apple's Hardware Diagnostics (no issues), tested it with Windows 11 using Boot Camp (fine too- I'm wondering if it's the Boot Camp, installation sometimes.).

I guess we'll have to wait for this year for the next OS upgrade after Monterey (but it's best to report this also to Apple using the Feeback app).

God bless.

Monterey 12.2 on an MP 6,1; three 4TB, one 1TB, and one 500 GB, all non-SSD WD, plus laser printer, either directly connected or thru USB hub. So far, so good, no problems.

Lots of problems mentioned here

I posted in a different thread before I saw this one, about my problems with external drives on my Air suddenly not working after updating to Monterey: Just to add to this thread, my 2020 (Intel) MacBook Air no longer likes my two WD 2TB external drives - WD Elements - which I use for backups, dismounting after between 1 and 10 minutes and trashing any transfer in progress. They were fine on Big Sur.

After buying a powered 4 port hub on Amazon (as before I saw this thread I assumed it was a power problem) they now work when connected through this, but not when connected directly. So my workaround is to use the hub (the brand is RSHTECH - I won't post a link as it will look like spam).

Sad to read about so many other people having issues, external drives are pretty critical for many of us. I hope Apple come up with a fix soon. I'm considering rolling back to Big Sur.

Ok folks, I hope this may be of some help.

I'm running a 2019 iMAC and came in at OSX 12.2 with a SSD on board and Sandisk Extreme SSD drives for backups, as well as some WD HDD for backups. first thing I did when upgrading was to make a SuperDuper backup of my OS drive. It failed half way through the copying stage. I'll not bore you with the steps I took in my frustration but nothing worked. I got an error message saying the disk could not be found half way through the copy. It had disappeared from my desktop and had greyed out when viewed in disk utility. It was simply there and then it was not. Tried several times after rebooting and downloading a new copy of SuperDuper. I was using the latest release in any event, which said it worked with Monterey. Reaching out to SuperDuper I had a reply within a few hours and was asked if I was plugging the external drive into a hub? I was. One of those Satachi 'fit under the bottom of the iMAC hobbies. Have used it for years without any problems, so much so I don't so much consider it a hub but an integral part of my iMac. On the advice from SuperDuper I connected directly into the iMac's USB-C port by way of a rear entry. Ran SuperDuper and sat and watched every byte being copied over. It was faultless and worked like a charm. I discovered later that Monterey is not recognising many USB hubs on the market. Apple have apparently known about this since Beta and here we are at 12.2 and still a patch has not been released. For those of you who are finding your external drives not working either connect directly into your main connections or look out for a hub that is known to work. Chances are it is not the drive being rejected, but the hub.

If Apple fixes this problem, I will be surprised because Apple wants all to get away from the older puters to the new. With that said, lol, I've been waiting to see what the new iMac will be like and I don't pay attention to the rumors of what it might be, I am waiting to see the real thing and yeah it's killing me

Thankfully after suffering for 4 months with no external backup, nor ability to mount dmg or any image files (so not way to install things, unless the download is auto extracting and mounting from the site owner), the new update 12.2 (just released today) seems to have fixed it, it's all working now- praise be Jesus, Mother Mary & St. Joseph!

I hope the networking to the PC printer has been fixed as well, so I can print from the Mac to the Windows 11 PC's printer (which doesn't have AirPrint, it's all CAT5, old school connected to the PC and the PC in turned if CAT5 connected to the fiber internet modem).

This'll still be observed, the report to the Feedback App seems to be very worth it.

God bless, Rev. 21:4