virtualbox.org

Have not been able to upgrade existing working virtual box installation since version 4.1. Uninstalled version 4.1 and cannot install older or newer version now.
Error on installation The specified path \\file-server1\Private\username\Application Data\Microsoft\Internet Explorer\Quick Launch\ is unavailable. This is every users drive location for part of their roaming profiles
However the location is verified. Any ideas?

Have you tried right-clicking the installer file and choosing "Run as Administrator"?

Yes "running as administrator" was tried on each version I attempted to install.

It just hit me, the installer is actually a Microsoft program. Since most folks don't have errors updating Virtualbox I'd say the Microsoft installer system on your PC is bunged up a bit. You might try asking on the MS forums about that error.

I'd also try asking the developers on the Bugtracker (https://www.virtualbox.org/wiki/Bugtracker) if they try or support installations on Windows accounts with roaming profiles.