Halo, I would ask for help from the experts,
I happened to upgrade R version to the latest version, 4.0.3 on my Mac OS Catalina,
the reason was that a package needed to be installed with the newest version, So, I just upgraded the R to the latest version, and now I am running into the problems that many packages can not be installed (and if they are installed) the libraries of the packages can not be loaded. I was advised that upgrading R to the latest was not a good decision (in our case: working on the same dataset/environment), so I uninstalled the latest version and back to R version 3.6.3, the problems are still there, can't install packages and load the libraries.
So far, some of those problematic packages are: adegenet, xlsx, deldir.
I have tried to run the command install.packages("lifecycle")
but it didn't help.
anybody with solutions is much appreciated.