Re: How do I check my SSD for damaged files?

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Gatekeeper would check on the first run, find the certificate is no longer current or the app doesn't match the original install version, and so complains that the app might be dangerous, when in reality it isn't dangerous and isn't corrupt.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.