Just in case others hit the same glitch. It's not directly an R issue, but if folk can't get an install to work, they are not going to use R. While I've always had a straightforward experience before, this install gave some troubles. I added the repository https://deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/ When I "saved" in Software Sources to add the additional repository, I got a malformed repository error. So I took out the "deb" bit of the line, and it was accepted. I added the key for Michael Rutter and checked it is not the second key as per http://rubuntu.netlify.com/post/changes-to-cran-ubuntu-webpage-regarding-apt-secure-key/ Then I got "The repository 'https://cloud.r-project.org/bin/linux/ubuntu bionic Release' does not have a Release file." Note no "-cran35". Turns out that Software Sources added a "bionic" so the repository line read deb https://deb https://cloud.r-project.org/bin/linux/ubuntu bionic bionic-cran35/ Took out the bionic and things worked fine. JN