Coot is an essential and functional software for structural biologist. I upgraded my Mac Studio to MacOS 26 yesterday and found that coot 0.9.8 cannot run, as well as 1.0, which was running well in former OS version. The information of my Mac Studio: M4 max chip, 64G memory. The description of coot: https://www2.mrc-lmb.cam.ac.uk/personal/pemsley/coot/.
Mac Studio, macOS 26.0
With 3rd party apps, your only real option is to contact the developer (his email is on the site you linked) about an update that is compatible with the updated macOS. That's even more true for academic software, as they may not have the resources to update the app while a new macOS is still in beta.
In the meantime, there are tutorials on downgrading to macOS 15 Sequoia, but that can be problematic.
Side note, I'll pass this info along to the computational chemist on my team, she does a fair bit of modeling and may use Coot on her Mac (though she does most of her modeling on a Schrödinger/Exxact workstation).
With 3rd party apps, your only real option is to contact the developer (his email is on the site you linked) about an update that is compatible with the updated macOS. That's even more true for academic software, as they may not have the resources to update the app while a new macOS is still in beta.
In the meantime, there are tutorials on downgrading to macOS 15 Sequoia, but that can be problematic.
Side note, I'll pass this info along to the computational chemist on my team, she does a fair bit of modeling and may use Coot on her Mac (though she does most of her modeling on a Schrödinger/Exxact workstation).
For your third party app—if in doubt search the developers website or contact their: Support/Help/FAQ/Known issues/compatibility/updates…
Contact a third-party vendor - Apple Support
Contact a third-party vendor - Apple Support
What did the developer say when you reported the problem to them?
You should really investigate potential compatibility problems with mission critical software before performing a major OS upgrade.
FYI, It is always best to either wait a while before upgrading to a new OS, or to do research on all third party apps & even the new OS to make sure they are compatible to the new OS & your workflow/needs, or to test the new OS on another Mac or external drive prior to upgrading the main internal boot drive. There is seldom any need to rush to a new OS...in fact some people will wait a year before upgrading.
This is even more important if a third party app is critical to your work.
Coot cannot use in the macOS Tahoe
