Hello Again Mr. DeFlaminis,
I'm certain that by now we're probably boring 98 percent of the community when they see these posts. 
Anyhow, that said: When the company IT purchased my machine, (HP 17" ZBook Laptop,) they more or less ignored my request for maxing out all the options, therefore when the ZBook, arrived it was "short sheeted" if I can use that term safely in these family oriented forums. On the sly, (without IT's permission,) I purchased upgrades and installed them myself. They purchased 16 gig of ram when the ZBook can use 32 gig, and they only provided a 250 gig harddrive.
Well by the time you put your O.S. and several other applications that a corporate IT department forces you to have to run, plus Office Suite and other minor softwares, well that 250 get's used up pretty quickly, and drastically cuts down on cache space. So knowing that I was slated to have Plant 3D Ultimate issued to me, as well as a couple other packages to allow for the processing of 3d scans ... I snagged a terabyte drive and installed as my D:, after that, I installed the full Plant 3D ultimate package. Plant 3D Ultimate came with 4 versions of AutoCAD, the plant software, Revit structure, Recap, Navisworks Manage, 3ds Max, 360, etc. I already had AutoCAD 2015 plain vanilla and MEP installed on my C: drive, and they're still there.
So to answer your questions finally, I installed all of the programs that came with Plant 3D on my 😧 drive in one sitting. No, it was not installed on C: then moved. As you know, installation programs automatically assume you're going to install your applications on your C: drive. But strange this error should be coming up for me only, when it appears it doesn't affect many others.
I look forward to hearing from you with the good news from your Registry guy(s)/gal(s).
Respectfully,
Ted Hadden
P.S. I don't do social media of any kind so the @ that you use in the front of my name doesn't do anything for me .... 