I tried to open a Disk Image file, and it wouldn't open. I tried all kinds of apps (including Disk Utility and Disk Image Mounter, obviously) but nothing would mount it. So I tried opening it on a machine running Mojave, and it opened without any problem.

I didn't know this was a thing. How to tell which disks won't mount under Monterey, so that I can convert them before the older system is gone for
ever?

Martin S Taylor

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

In article <0001HW.28C8ABA4002D403E70000BF3338F@news.eternal-september.org>, Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

I tried to open a Disk Image file, and it wouldn't open. I tried all kinds of >apps (including Disk Utility and Disk Image Mounter, obviously) but nothing >would mount it. So I tried opening it on a machine running Mojave, and it >opened without any problem.

Odd. What does the "file" command say about it, e.g.

$ file rr2.dmg

rr2.dmg: DOS/MBR boot sector, code offset 0x34+2, OEM-ID "MSDOS3.3", sectors/cluster 2, root entries 112, sectors 1440 (volumes <=32 MB), Media descriptor 0xf9, sectors/FAT 3, sectors/track 9, dos < 4.0 BootSector (0), FAT (12 bit by descriptor),
followed by FAT

-- Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 7 Sep 2022 at 11:36:20 BST, "Martin S Taylor" <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

I tried to open a Disk Image file, and it wouldn't open. I tried all kinds of apps (including Disk Utility and Disk Image Mounter, obviously) but nothing would mount it. So I tried opening it on a machine running Mojave, and it opened without any problem.

I didn't know this was a thing. How to tell which disks won't mount under Monterey, so that I can convert them before the older system is gone for ever?

Martin S Taylor

I'd expect that to mean it's damaged in a way that Monterey refuses to
touch for safety reasons, rather than it being intentionally in a
changed format.

What results do you get in Disk Utility if you go to Images/Verify and
scan the dmg?

Cheers - Jaimie
--
I love children, especially when they cry, for then someone takes them away.
-- Nancy Mitford

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 7 Sep 2022 at 16:00:32 BST, "Jaimie Vandenbergh" <jaimie@usually.sessile.org> wrote:

On 7 Sep 2022 at 11:36:20 BST, "Martin S Taylor" <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

I tried to open a Disk Image file, and it wouldn't open. I tried all kinds of
apps (including Disk Utility and Disk Image Mounter, obviously) but nothing >> would mount it. So I tried opening it on a machine running Mojave, and it
opened without any problem.

I didn't know this was a thing. How to tell which disks won't mount under
Monterey, so that I can convert them before the older system is gone for
ever?

Martin S Taylor

I'd expect that to mean it's damaged in a way that Monterey refuses to
touch for safety reasons,

Oh - unpacking that a bit: there was a flap some years ago about
intentionally malformed .dmgs being used as a stack-breaking attack
vector. Double-click to pwn type thing. Yours may not be intentionally malformed, but hitting the same protective measures.

Cheers - Jaimie
--
'It's one of those irregular verbs, isn't it? `I protect the
lives and property of my citizens; you keep the public
safe from an unreasonable and trouble-generating
minority; he maintains a totalitarian regime of
thought control.' -- Bernard, Yes Minister

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sep 7, 2022, Jaimie Vandenbergh wrote
(in article <jnrq0gFoaf1U1@mid.individual.net>):

What results do you get in Disk Utility if you go to Images/Verify and
scan the dmg?

Operation failed...
Resource temporarily unavailable

MST

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

In article <jnrq0gFoaf1U1@mid.individual.net>,
Jaimie Vandenbergh <jaimie@usually.sessile.org> wrote:

I'd expect that to mean it's damaged in a way that Monterey refuses to
touch for safety reasons, rather than it being intentionally in a
changed format.

Surely it would display an error message in that case? Especially if
it's a possible attack - otherwise the user is likely (as we've seen)
to copy it to another computer.

-- Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sep 7, 2022, Richard Tobin wrote
(in article <tfa7ru$21ki$1@macpro.inf.ed.ac.uk>):

In article<0001HW.28C8ABA4002D403E70000BF3338F@news.eternal-september.org>, Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

I tried to open a Disk Image file, and it wouldn't open. I tried all kinds of
apps (including Disk Utility and Disk Image Mounter, obviously) but nothing would mount it. So I tried opening it on a machine running Mojave, and it opened without any problem.

Odd. What does the "file" command say about it, e.g.

$ file rr2.dmg

rr2.dmg: DOS/MBR boot sector, code offset 0x34+2, OEM-ID "MSDOS3.3", sectors/cluster 2, root entries 112, sectors 1440 (volumes <=32 MB), Media descriptor 0xf9, sectors/FAT 3, sectors/track 9, dos < 4.0 BootSector (0), FAT (12 bit by descriptor), followed by FAT

-- Richard

/Users/mst/Desktop/Gardner.dmg: ISO 9660 CD-ROM filesystem data 'Gardner'

MST

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

In article <0001HW.28C9D9A40058963870000771F38F@news.eternal-september.org>, Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

/Users/mst/Desktop/Gardner.dmg: ISO 9660 CD-ROM filesystem data 'Gardner'

That looks vanilla enough. Jaimie, did the malformed dmg issue
you mentioned apply to ISO 9660?

-- Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 8 Sep 2022 at 11:26:54 BST, "Richard Tobin" <Richard Tobin> wrote:

In article <0001HW.28C9D9A40058963870000771F38F@news.eternal-september.org>, Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

/Users/mst/Desktop/Gardner.dmg: ISO 9660 CD-ROM filesystem data 'Gardner'

That looks vanilla enough. Jaimie, did the malformed dmg issue
you mentioned apply to ISO 9660?

No idea, I don't think anything was detailed.

Hmm, https://nvd.nist.gov/vuln/detail/CVE-2015-3800 was too early for it
to be the macos transition Martin's on anyway.

Cheers - Jaimie

--
"No flying cars yet?", he wrote from a 2 inch by 4 inch
pocket computer instantaneously to subscribers
worldwide using only his right thumb.
-- @wjflowers

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 7 Sep 2022 at 23:45:25 BST, "Richard Tobin" <Richard Tobin> wrote:

In article <jnrq0gFoaf1U1@mid.individual.net>,
Jaimie Vandenbergh <jaimie@usually.sessile.org> wrote:

I'd expect that to mean it's damaged in a way that Monterey refuses to
touch for safety reasons, rather than it being intentionally in a
changed format.

Surely it would display an error message in that case?

Well, Apple. You know. The ones who made the macOS system logs almost impossible for human users to read for issue analysis.

Cheers - Jaimie

--
People who think they know everything really annoy those of us who know we don't
-- Bjarne Stroustrup

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Martin S Taylor <correspondence@mraermtoivnestthaiyslor.com> wrote:

/Users/mst/Desktop/Gardner.dmg: ISO 9660 CD-ROM filesystem data 'Gardner'

What happens if you rename it to .iso rather than .dmg?

(it would still need to be opened in Disk Utility)

Theo

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sep 8, 2022, Theo wrote
(in article <rXj*vvNXy@news.chiark.greenend.org.uk>):

What happens if you rename it to .iso rather than .dmg?

Same.

MST

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

In article
<0001HW.28CA30E9006A3DCE70000ACD138F@news.eternal-september.org>,
Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

What happens if you rename it to .iso rather than .dmg?

Same.

you said you can open it on mojave, so my suggestion is to do that and
use carbon copy cloner to copy everything to a new disk image.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sep 8, 2022, nospam wrote
(in article<080920221022035735%nospam@nospam.invalid>):

In article
<0001HW.28CA30E9006A3DCE70000ACD138F@news.eternal-september.org>,
Martin S Taylor <correspondence@mRaErMtOiVnEsTtHaIySlor.com> wrote:

What happens if you rename it to .iso rather than .dmg?

Same.

you said you can open it on mojave, so my suggestion is to do that and
use carbon copy cloner to copy everything to a new disk image.

I did that before I made the original post. It worked well. I was just
puzzled that such a problem was possible.

MST

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)