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Comment by mulmen | Hacker News Reader

This is unexpected to me. If I remove an application I do not expect it to run. If the OS is willing to reach into the Time Machine backups will it also modify them? What if I delete an app, run it then install an update? Will it install to the backup? That would be very unexpected.

Looking at multiple application directories is one thing but executing things from the backup directory is another.

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I checked before, and if I recall correctly, Time Machine backups are protected at the kernel level -- you cannot modify them, even with sudo. You can delete the whole backup, but you cannot modify part of it.

> but executing things from the backup directory is another.

Time Machine backups are structured in a very non-proprietary way. Each backup is just a folder, protected from modifications, with hard links used to save space. If anything, I'd say good on Apple for supporting a backup format that works exactly like making a copy of a folder.

Sure nothing wrong with the format of the backups, that makes total sense. What doesn't make sense is executing things in those directories.

You can also delete items from your backup. So like if wanted to delete Zoom from Time Machine just select it in a backup and then select the option to remove it from all your backups from the Action menu or a right-click.

Ok but why would I do that? The whole idea of a backup is that I can... go back.

Do other apps launch from backups like this? It’s very strange.

My expectation is that if I want to go back to a backup I have to restore that backup first then run the application. Executing from a backup is surprising and frankly difficult to reason about. What version is even running? How would I know?

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