[2021] Launcher Install problems

Please delete the whole contents of that /Installer/ folder (NOT the folder itself). They are all temporary files.

That should do it!  

In File Explorer click on This PC , then on Local Disk C: . You should see the /Windows/ folder; double click on that and you should see that Installer folder.  

Sorry, I forgot that it's hidden by MS. Click on View up the top there and tick Hidden Items and File Extensions.  

That is a core Windows folder, put there at installation time I believe. I can't understand how it can not be there for you, it doesn't seem likely you deleted it accidentally.

Can you make a folder with that name there then?