Windows: Errors trying to upgrade, install, or uninstall Plex Media Server

I can't upgrade or fresh install Plex Media Server on my Windows 10 64-bit. Error is 0x80070643.

I have tried both suggestions in this support page and neither work:

https://support.plex.tv/hc/en-us/articles/202967086-Windows-Errors-trying-to-upgrade-install-or-uninstall-Plex-Media-Server

Windows is fully updated, yet I still get the error: "The feature you are trying to use is on a network resource that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'vc_runtimeMinimum_x86.msi'

Please help - thank you

James