This page provides details on the uninstall process for V-Ray in Revit.
Overview
V-Ray installer automatically uninstalls any previous versions. Uninstalling V-Ray from Revit does not uninstall Chaos Cloud Client, Chaos Cosmos Browser, Chaos License Server, Chaos Unified Login and V-Ray Swarm. Those can be uninstalled separately if needed.
Uninstall
If you need to manually uninstall V-Ray, make sure that Revit or V-Ray components are not being used.
Then open the Windows Start Menu > All apps > Chaos > Uninstall V-Ray for Revit or alternatively run the Uninstall.lnk located in C:\Program Files\Chaos\V-Ray\V-Ray for Revit\uninstall.
For versions prior to V-Ray 7, the default location of the Uninstall.lnk file is C:\Program Files\Chaos Group\V-Ray\V-Ray for Revit\uninstall.
This starts the V-Ray uninstaller. Follow the on-screen instructions to remove V-Ray from your system and restore any files overwritten by the installation.