[pobstar]

I noticed the Windows download has an expired certificate from Startcom, which has not been trusted by most browsers for some time.

I'm reluctant to go ahead with the install because of this - is anyone aware of plans for a new cert to be applied, or if the packaged is hosted on some other mirrors somewhere else?

 

[pobstar]

Did you get it from here?
Mazda AIO Tweaks

Yes.
I'm on Windows 10 Pro, v 1909, build 18363.592 and downloaded via Chrome, v 79.0.3945.130, though I don't think those specs are the issue - I also tried on another Win10 PC with different specs without success.
Same issue on both the windows downloads (dl.mazdatweaks.win and dl32.mazdatweaks.win).