Solved by Frankco, TX.
Hi, I can't install this latest daily build on my iMac OSX 10.14.6
The installer installs in the R20 folder and does not recognize the "Applications/Maxon Cinema 4D R21" folder
R21 is actually differently installed by the Maxon installer in a folder that is named "Maxon Cinema 4D R21" It used to be "Applications/Maxon/Cinema 4D R20"
I tried to manually move the installed Corona Plugin folder from R20 to the R21 plugin folder but it did not work. The plugin in the R20 folder is named corona4dR20.xlib so maybe the installer does not install a R21 compatible plugin in the R20 folder.
Anyhow, hope the team fixes this asap. I feel a little left out now...