I used WIFI to migrate from an M1 Mac to an M4, both running OS 15.1.
Thunderbird still worked on the M1, but when I tried to launch it on the
M4, the system said it was damaged and should be discarded.

I downloaded and installed a replacement. Do files get corrupted in
migration? Is it possible that the App simply needed the install process
on the M4 to work on the M4?

I'm worried that somewhere an important word-processing, spreadsheet,
pdf, or jpg may be corrupted. If I next need it after 5 years, a good
copy may no longer be available. Time Machine disks don't last forever.

I want to know now if any files need replacement. Would Time Machine
detect bad files? Backups have gone smoothly.

How about Disk First Aid? Maybe I should run it on principle. It
suggests that I use Recovery because the computer will be unresponsive
for minutes or hours. I don't see the point of that advice. Won't my
computer also be unusable if booted in Recovery?

Do I need a third-party utility?

On 2024-11-11 09:50, J Burns wrote:
> I used WIFI to migrate from an M1 Mac to an M4, both running OS 15.1.
> Thunderbird still worked on the M1, but when I tried to launch it on the
> M4, the system said it was damaged and should be discarded.
>
> I downloaded and installed a replacement. Do files get corrupted in
> migration? Is it possible that the App simply needed the install process
> on the M4 to work on the M4?
>
> I'm worried that somewhere an important word-processing, spreadsheet,
> pdf, or jpg may be corrupted. If I next need it after 5 years, a good
> copy may no longer be available. Time Machine disks don't last forever.
>
> I want to know now if any files need replacement. Would Time Machine
> detect bad files? Backups have gone smoothly.
>
> How about Disk First Aid? Maybe I should run it on principle. It
> suggests that I use Recovery because the computer will be unresponsive
> for minutes or hours. I don't see the point of that advice. Won't my
> computer also be unusable if booted in Recovery?
>
> Do I need a third-party utility?

This is not actually about data corruption.

This is about either an extended attribute being set to "quarantine" the
file.

Data files won't get this message, so you don't have to worry.

On 2024-11-11 17:50:39 +0000, J Burns said:
>
> I used WIFI to migrate from an M1 Mac to an M4, both running OS 15.1.
> Thunderbird still worked on the M1, but when I tried to launch it on
> the M4, the system said it was damaged and should be discarded.

That sounds like the usual MacOS Gatekeeper anti-malware system
message. It usually means nothing (unless you're downloading dodgey
pirate apps) and can be bypassed, although gets more difficult with
every new version of MacOS.

Gatekeeper would check on the first run, find the certificate is no
longer current or the app doesn't match the original install version,
and so complains that the app might be dangerous, when in reality it
isn't dangerous and isn't corrupt. Possibly the developer's certificate
was fine when the app was first run on the old computer, but for some
reason had been changed (e.g. renewed under a different name) by the
time it was first run on the new computer. Some apps alter themselves
after install for things like preference settings, auto-updates done
via the internal check, etc.

> I downloaded and installed a replacement. Do files get corrupted in
> migration? Is it possible that the App simply needed the install
> process on the M4 to work on the M4?
>
> I'm worried that somewhere an important word-processing, spreadsheet,
> pdf, or jpg may be corrupted. If I next need it after 5 years, a good
> copy may no longer be available. Time Machine disks don't last forever.
>
> I want to know now if any files need replacement. Would Time Machine
> detect bad files? Backups have gone smoothly.
>
> How about Disk First Aid? Maybe I should run it on principle. It
> suggests that I use Recovery because the computer will be unresponsive
> for minutes or hours. I don't see the point of that advice. Won't my
> computer also be unusable if booted in Recovery?
>
> Do I need a third-party utility?

Since the app almost certainly was not corrupt, I wouldn't waste your time.

On 11/11/24 4:30 PM, Your Name wrote:
> On 2024-11-11 17:50:39 +0000, J Burns said:
>>
>> I used WIFI to migrate from an M1 Mac to an M4, both running OS 15.1.
>> Thunderbird still worked on the M1, but when I tried to launch it on
>> the M4, the system said it was damaged and should be discarded.
>
> That sounds like the usual MacOS Gatekeeper anti-malware system message.
> It usually means nothing (unless you're downloading dodgey pirate apps)
> and can be bypassed, although gets more difficult with every new version
> of MacOS.
>
> Gatekeeper would check on the first run, find the certificate is no
> longer current or the app doesn't match the original install version,
> and so complains that the app might be dangerous, when in reality it
> isn't dangerous and isn't corrupt. Possibly the developer's certificate
> was fine when the app was first run on the old computer, but for some
> reason had been changed (e.g. renewed under a different name) by the
> time it was first run on the new computer. Some apps alter themselves
> after install for things like preference settings, auto-updates done via
> the internal check, etc.

Thank you! I wish Apple had made it clear.
>
>

>>
>> Do I need a third-party utility?
>
> Since the app almost certainly was not corrupt, I wouldn't waste your time.
>
>

I did waste 65 seconds running First Aid. I think the warning that it
could take hours was hogwash, as was the recommendation that running it
from Recovery would help. Sequoia isn't compatible with any Mac before
2018, and I guess the biggest internal drive is 1 TB SSD. How could it
take hours?

On 2024-11-12 16:00:38 +0000, J Burns said:
> On 11/11/24 4:30 PM, Your Name wrote:
>> On 2024-11-11 17:50:39 +0000, J Burns said:
>>>
>>> I used WIFI to migrate from an M1 Mac to an M4, both running OS 15.1.
>>> Thunderbird still worked on the M1, but when I tried to launch it on
>>> the M4, the system said it was damaged and should be discarded.
>>
>> That sounds like the usual MacOS Gatekeeper anti-malware system
>> message. It usually means nothing (unless you're downloading dodgey
>> pirate apps) and can be bypassed, although gets more difficult with
>> every new version of MacOS.
>>
>> Gatekeeper would check on the first run, find the certificate is no
>> longer current or the app doesn't match the original install version,
>> and so complains that the app might be dangerous, when in reality it
>> isn't dangerous and isn't corrupt. Possibly the developer's certificate
>> was fine when the app was first run on the old computer, but for some
>> reason had been changed (e.g. renewed under a different name) by the
>> time it was first run on the new computer. Some apps alter themselves
>> after install for things like preference settings, auto-updates done
>> via the internal check, etc.
>
> Thank you! I wish Apple had made it clear.
>
>
>> Do I need a third-party utility?
>>
>> Since the app almost certainly was not corrupt, I wouldn't waste your time.
>
> I did waste 65 seconds running First Aid. I think the warning that it
> could take hours was hogwash, as was the recommendation that running it
> from Recovery would help. Sequoia isn't compatible with any Mac before
> 2018, and I guess the biggest internal drive is 1 TB SSD. How could it
> take hours?

Disk First Aid can't repair some potential problems when booting and
running it from the same disk because it needs to unmount the drive.
Starting up from the Recovery partition and using that copy of Disk
First Aid allows the usual boot drive to be unmounted if needed.

It shouldn't take "hours", especially on an SSD, but can take a while
if you have lots and lots of files and/or a huge capacity drive.

On 11/12/24 2:48 PM, Your Name wrote:
> On 2024-11-12 16:00:38 +0000, J Burns said:

>> I did waste 65 seconds running First Aid. I think the warning that it
>> could take hours was hogwash, as was the recommendation that running
>> it from Recovery would help. Sequoia isn't compatible with any Mac
>> before 2018, and I guess the biggest internal drive is 1 TB SSD. How
>> could it take hours?
>
> Disk First Aid can't repair some potential problems when booting and
> running it from the same disk because it needs to unmount the drive.
> Starting up from the Recovery partition and using that copy of Disk
> First Aid allows the usual boot drive to be unmounted if needed.
>
> It shouldn't take "hours", especially on an SSD, but can take a while if
> you have lots and lots of files and/or a huge capacity drive.
>
>
Apple's message says running from Recover would avoid leaving the
computer responsive for long.

"Verifying the startup volume will cause this computer to stop
responding. This may last for several minutes to several hours. To avoid
this, you can run First Aid while in Recovery."

I don't understand. Besides, the last time Disk First Aid took long for
me, it was a mechanical drive with countless Time Machine backups.

On 11/12/24 2:48 PM, Your Name wrote:
> On 2024-11-12 16:00:38 +0000, J Burns said:

>> I did waste 65 seconds running First Aid. I think the warning that it
>> could take hours was hogwash, as was the recommendation that running
>> it from Recovery would help. Sequoia isn't compatible with any Mac
>> before 2018, and I guess the biggest internal drive is 1 TB SSD. How
>> could it take hours?
>
> Disk First Aid can't repair some potential problems when booting and
> running it from the same disk because it needs to unmount the drive.
> Starting up from the Recovery partition and using that copy of Disk
> First Aid allows the usual boot drive to be unmounted if needed.
>
> It shouldn't take "hours", especially on an SSD, but can take a while if
> you have lots and lots of files and/or a huge capacity drive.
>
>
Apple's message says running from Recover would avoid leaving the
computer unresponsive for long.

"Verifying the startup volume will cause this computer to stop
responding. This may last for several minutes to several hours. To avoid
this, you can run First Aid while in Recovery."

I don't understand. Besides, the last time Disk First Aid took long for
me, it was a mechanical drive with countless Time Machine backups.

On 2024-11-13 11:26, J Burns wrote:
> On 11/12/24 2:48 PM, Your Name wrote:
>> On 2024-11-12 16:00:38 +0000, J Burns said:
>
>>> I did waste 65 seconds running First Aid. I think the warning that it
>>> could take hours was hogwash, as was the recommendation that running
>>> it from Recovery would help. Sequoia isn't compatible with any Mac
>>> before 2018, and I guess the biggest internal drive is 1 TB SSD. How
>>> could it take hours?
>>
>> Disk First Aid can't repair some potential problems when booting and
>> running it from the same disk because it needs to unmount the drive.
>> Starting up from the Recovery partition and using that copy of Disk
>> First Aid allows the usual boot drive to be unmounted if needed.
>>
>> It shouldn't take "hours", especially on an SSD, but can take a while
>> if you have lots and lots of files and/or a huge capacity drive.
>>
>>
> Apple's message says running from Recover would avoid leaving the
> computer unresponsive for long.
>
> "Verifying the startup volume will cause this computer to stop
> responding. This may last for several minutes to several hours. To avoid
> this, you can run First Aid while in Recovery."
>
> I don't understand. Besides, the last time Disk First Aid took long for
> me, it was a mechanical drive with countless Time Machine backups.

It's quite possible that the message hasn't been updated since HDDs were
standard, but even if it has, they're just covering themselves.

Who's to say that a disk with a lot of damage couldn't possibly take a
long time to verify and/or repair?

On 13. Nov 2024 at 20:26:28 CET, "J Burns" <burns@nospam.com> wrote:

> "Verifying the startup volume will cause this computer to stop
> responding. This may last for several minutes to several hours. To avoid
> this, you can run First Aid while in Recovery."

The important word here is MAY!

It´s just to let the user know that it COULD take a long time so that he
knows and does not think the machine is frozen.