Tip: If you have restricted access to the Windows computer you're logged into you may not be able to access the Windows Registry. Once opened successfully you should be in the Windows Registry Editor Window, similar to the example shown below.If prompted by User Account Control, click Yes to open the Registry Editor.In the Start Menu either in the Run Box or Search box type regedit and press Enter. Typically the Windows Installer clears these keys, but not in this case. Then verify that Revit related registry keys listed below are removed from the system after Revit is uninstalled. Resolution: For a clean Revit 2020 / 2021 / 2022 installation, uninstalled any/all Revit related software from the Windows Control Panel. Templates and families not installed Revit 2020 / 2021 / 2022?.You're unable to install Revit 2020 / 2021 / 2022 again.

When you attempt to reinstall Revit 2020 / 2021 / 2022, the installer reports Revit as already being installed, which you know is not true, since you just uninstalled Revit 2020 / 2021 / 2022.

You have uninstalled Revit 2020 / 2021 / 2022 and need to reinstall.

Download your Autodesk installers from the 'Autodesk-Student' share here: Software Downloads

The Revit 2021 / 2022 installer you've downloaded from Autodesk is corrupt and will not install correctly.

Revit 2021 student