I don't think that your issues are related to this Rig Manager release. If the installer (which is an MS product) cannot install the required files, Rig Manager cannot work as expected. Also, an icon doesn't just vanish (especially when the app is not even launched). You might want to look into your Windows installation.
I agree that was a sort of incident, I fixed it Windows-side with a trick or two.
I continue to not be able to see the arrow and buttons (within RM) I mentioned in my original comment tho.
This is what I see (1920x1080) on my screen. Video Card is a simple
AMD Radeon HD 5450 I've been using since years.
I changed nothing in my setup, video settings, resolution and the like: just installed 3.3.40 R (and later on .43 R) like I've always done.
Any help (or the installer for a previous R version of RM) would be appreciated.