Photoshop 25 won't open ( m4 Mac)

Uninstall Photoshop, then reinstall. That's the most likely and simplest fix. Next level would be to sign out of your Adobe account, then sign back in. Sometimes weird stuff happens when an OS updates, and it's not uncommon that things suddenly don't "just work" anymore.

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

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