Windows 10 Pro 64-bit
The exact same thing is also happening for Defraggler:
dfgPortable also is hanging during installation at "Create folder: I:\PortableApps\specPortable\App\Defraggler"
In both cases, they are new installations, as opposed to updates.
This is usually due to either a drive issue or something on your PC blocking it but not alerting you to the fact that it is blocking it (some antivirus/antimalware utilities are annoying like that). At the point you mention, it's just NSIS dumping files onto the drive similar to unzipping something, none of the special sauce code we add to handling upgrades, licensing, etc, so whatever is going on isn't something in our purview.
Sometimes, the impossible can become possible, if you're awesome!