It seems that I can't install any source package. The error message is always like:
cannot open file 'myin$/Documents/R/win-library/3.5/glue/doc/index.html': No such file or directory
Error in file(con, "w") : cannot open the connection
R is notoriously bad at working with file paths involving unusual characters which I think includes $. The easiest solution I can think for you is to make a new user profile with a name using purely the alphabet.