When installing Autodesk's Revit 2018 Security Fix I kept getting an error that a newer version was installed. I have other versions of Revit installed but I would assume that a Revit update labeled with the version (2018) wouldn't interfere with other versions. I found this to be a small hurdle.
This is regarding the June 15th deadline to install the Personal Accelerator for Revit Security Fix. This security fix needs to be installed to maintain connectivity with your Revit Cloud Models Services. You can get this security fix from the Autodesk Desktop App or through your Autodesk account
I was not able to install the Personal Accelerator for Revit 2018 Security Fix because it was seeing a different version already installed and I was not able to uninstall the Personal Accelerator for Revit from control panel. The way I was able to see the versions that were installed was to use the free software IObit Uninstaller and uninstall it.
I didn't use the Microsoft Fixit tool because it didn't show me that there were more than one versions of the Personal accelerator still installed and I wasn't completely comfortable with just uninstalling the Personal Accelerator. IObit showed that I had two versions of the Personal Accelerator installed and there was an old version 16.0.1205.0 installed so I had IObit remove that version and I left the other one that was version 126.96.36.199 because I still needed to install the security fix for 2019 and 2020.
After that hurdle I was able to install the 2019 2020 Personal Accelerator for Revit with no issues.