I would be helpful to know your computer setup.
I am assuming that you were using AMD Wattman in Radeon Settings correct?
What exact errors to you get when you try to open AMD Wattman?
Whatever Computer system you are using, Apply this basic method of removing all traces of your current AMD Driver and see if Radeon Settings works correctly afterwards:
Uninstall the current AMD Driver using DDU as per this method:
It could be due to a corrupted AMD Driver installation.
Download free program DDU (Display Driver Uninstaller). Run it in Safe mode with the internet disconnected.
You can also run it in Windows Desktop but then you would need to Reboot the computer for DDU to finish erasing all of the AMD Driver traces from your computer.
Once it finishes uninstalling the current AMD Driver in Safe mode and boots back to Windows Desktop, still with the Internet disconnected, delete the AMD Installation folder C:\AMD if it was created before.
Now install the full AMD Drive package you downloaded manually from AMD Download page. Not the express package. Run the package and if it installs correctly again delete C:\AMD folder and reconnect the internet.
This should prevent any conflict when installing the new version from the previous version.
By the way, C:\AMD is always created whenever you run the AMD Driver package
