Windows installer can install into non-existing location, blocking re-/uninstall
The Windows installer for Gstreamer sometimes suggests weird default installation destinations, e.g. g:\gstreamer even if drive g: doesn't exist. I failed to correct this once and carelessly launched the installation process which completed without a single warning that the location did not in fact exist. When I noticed the mistake, I wanted to uninstall / reinstall the package; alas, it wasn't possible since the installer aborted when it couldn't locate the non-existent g: drive. In the end, removing all gstreamer-related registry entries containing g:\gstreamer helped - I didn't spend much time on figuring out which specific one was the culprit.
The behaviour of suggesting bad locations seems to occur on some computers, whereas on most others c:\gstreamer comes up.