I have reinstalled it and the sliders work now. but the default shortcuts dont adjust the screens anymore.

In my case, as soon as I manually change the brightness in the original Mac screen, either via brightness buttons or the sliders, the app crashes. It happened after the upgrade to MacOS 15.

Please try the latest version. https://github.com/MonitorControl/MonitorControl/releases

Due to a change in app signature, if you are still running v4.2.0, auto-update will not work. You need to download and install this version manually.

This should be big in the README:

Due to a change in app signature, if you are still running v4.2.0, auto-update will not work.

I am using the homebrew version and I was not aware it wasn't updated anymore, but stuck on 4.2.0. I've run into issues with Sequoia 15.1 (basically the app was not working at all). After reading this I fixed it by turning it off and on again re-installing it:

brew uninstall --cask monitorcontrol

brew install --cask monitorcontrol

And now with version 4.3.3 it works like a charm again.

Thanks for maintaining this nifty little tool!

I was facing this issue as well where as soon as you would change the brightness of your native display (laptop's display) brightness, it would crash.
Thankfully, first uninstalling it completely using an app like AppCleaner, to completely remove all library dependency files.

Then using @mediafinger brew command

brew install --cask monitorcontrol

OR, manually downloading the new v4.3.3 from the github page has now RESOLVED the issue and everything is working GREAT.

Thank you very much for maintaining such a great tool.

FYI --cask is deprecated, brew reinstall monitorcontrol is enough.

I was using MonitorControl since the Sequoia update coincidentally without noticing the crashing issue, as I only use it for a non-HDR external monitor. I've even periodically checked for updates, not knowing I'd never get another reported update. Thought it was a bit weird to keep seeing "You're up to date!" but assumed that the maintainers had really done their homework to keep everything working for the Sequoia support. It wasn't until my curiosity caused me to click the Version History button. Brilliant idea to update that version history page with the disclaimer though! It did jump right out and gave all the info I needed.

But it really seems like a dropped ball for the update check to confirm latest. I assume that check is in Apple's hands, but is there no way to invalidate the old key/release or otherwise push some kind of new release so it can "detect an update" that leads you to the info on needing manual update? At least a final update using the old signature to install a "no-changes update" or dummy app that just informs that a manual update is required for new versions. Even a response from the server that would tell users to update manually might be more helpful.

Seems like there's probably a fair number of users out there that just won't find their way to this info. If I had noticed the crashes, I'd first try the Check for update button. But when an app reports that it's "up-to-date" but doesn't function correctly, it'll probably get the uninstall treatment by most users eventually.

Luckily the Version History button was there, but I'm the type of user that would actually click that. Then again, I'm also the type of user that reviews license agreements to find out what I'm actually giving away--not your typical user.

@eltoddo - yes, this is an issue. However I can't do much about it, there is no way to release an update with the old keys. Maybe I could do a fake update that has only a release notes explaining the situation and then fail, but that would be inelegant and confusing too.

I didn't know 4.2.0 wouldn't auto-update. After updating to MacOS 15.1, I started facing the exact issue as @Rakshit-Yadav. Uninstalling/Installing (as with the new --reinstall) worked for me! Thanks guys!

Same issue here of course, adjusting brightness of external monitor worked but adjusting the brightness of the MacBook screen crashed the app after updating to macOS 15.1.

For a while I didn't know there was an update after v4.2.0 like everyone else. Now manually updated to v4.3.0. and everything works fine again, thanks.

Maybe this is a wake-up call to implement an alternative way to notify users about updates, maybe a generic event/news view or something. I think a lot of users will be stuck on 4.2.0 for a long time (until they decide to either just abandon the app or go to the GitHub page and find out there is a new version).

As far as I see users are finding the new version all right. :) For those who are on older macOS versions, running 4.2.0 is fine. Even those are mostly fine who upgrade to Sequoia but only use third party displays. The best I could do to address this is to push a "fake" update to older clients that shows a release notes message (many users are wired to ignore such things) about the need to upgrade - but actually fails to do so with an error. But this would cause issues to users who set the app to auto-update and simply create more confusion.

Uninstall & install works for me.

monitorcontrol 4.3.3
macOS 15.2

I think a minor update e.g. 4.2.1 just to show a message to users they must manually update is a good idea. It could be shown instead of the "there is no update" message.