I tried clean install multiple times, manually checking every single temporary folders for any residuals after uninstallation. However, I did not check Registry as I don't have clear idea of where Rainmeter's registry would be. So if you can help me on that, it would be awesome.Alternatively to Xenium's solution, if for some reason his approach is not preferred (though I can't see why it wouldn't)...
I don't use Spotify or the skin you mentioned, so I can't advise on that, but if it works in the sandbox and not on the main computer while having the same environment on the Rainmeter related side, this would suggest that a clean install (i.e. no traces of the previous installation) of Spotify is needed. Additionally, to replicate what the sandbox does, any updates or stuff that would potentially alter the initial (and presumably working) installation and its (registry or otherwise) settings would probably be best left disabled (or blocked). I don't know if it helps, but that's what I would do in a similar situation.
Statistics: Posted by teastme12 — Yesterday, 2:31 pm