The third-party app uninstaller that I downloaded from the App Store seems doesn’t work on my iMac running macOS Sonoma. Can anyone tell me why?
Which app uninstaller have you downloaded from the App Store? Perhaps the software you downloaded is not compatible with macOS Sonoma. You can delete it and try a different one.
The app uninstaller that I use is CleanMyApp. It is a freeware that I heard from my friend. This app can list all third-party apps on your Mac and their associated files. You just select the app you want to delete, it will immediately remove it and its leftovers from your Mac.
Usually, apps downloaded from the App Store are safe and authenticated by Apple. So, you don’t need to worry about whether you’ve downloaded any malware.
The reasons why you can’t use it in macOS Sonoma may because one of these:
The app installer is broken due to an unstable network.
The app is not free. You need to pay for it before using it.
The app is not supported by macOS Sonoma.