It turns out that VC++ 2017 redistributables are the culprit because they delete the registry keys used by VC++ 2015 redistributables.
See this Microsoft Developer Community page for solution (TL;DR; you have to repair VC++ 2017 redistributables as this will restore missing 2015 registry keys).
This process is as Eric describes:
The steps are essentially: go to Programs in Control Panel (or “Add or Remove Programs” in Windows 10’s “Settings”), find the Microsoft Visual C++ 2017 Redistributable, click it and choose Change/Modify, then choose “Repair