Loading packages in R and RStudio gives image not found error - r

Question

When trying to load packages in RStudio or R, I get "image not found" errors, e.g.:
> install.packages("Rcpp")
Installing package into ‘/Users/blah/Library/R/4.0/library’
(as ‘lib’ is unspecified)
trying URL 'https://cran.rstudio.com/bin/macosx/contrib/4.0/Rcpp_1.0.6.tgz'
Content type 'application/x-gzip' length 3203922 bytes (3.1 MB)
==================================================
downloaded 3.1 MB
The downloaded binary packages are in
/var/folders/q5/9z9mngy52lx6gbjtc_tg5w2wwn7x6k/T//RtmpZwoJ1y/downloaded_packages
> library(Rcpp)
Error: package or namespace load failed for ‘Rcpp’ in dyn.load(file, DLLpath = DLLpath, ...):
unable to load shared object '/Users/blah/Library/R/4.0/library/Rcpp/libs/Rcpp.so':
dlopen(/Users/blah/Library/R/4.0/library/Rcpp/libs/Rcpp.so, 6): Library not loaded: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libR.dylib
Referenced from: /Users/blah/Library/R/4.0/library/Rcpp/libs/Rcpp.so
Reason: image not found
> detach("package:Rcpp", unload = TRUE)
Error in detach("package:Rcpp", unload = TRUE) : invalid 'name' argument
The same thing happens for many other packages in the User Library e.g. sp, kernlab, gplots, gtools (but not all of them e.g. crayon loads ok). Packages in the System library load fine.
Similar things happen in R, but not with the same set of packages e.g. Rcpp works here but kernlab still does not:
> library(Rcpp)
> detach("package:Rcpp", unload = TRUE)
> library(kernlab)
Error: package or namespace load failed for ‘kernlab’ in dyn.load(file, DLLpath = DLLpath, ...):
unable to load shared object '/Users/blah/Library/R/4.0/library/kernlab/libs/kernlab.so':
dlopen(/Users/blah/Library/R/4.0/library/kernlab/libs/kernlab.so, 6): Library not loaded: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRblas.dylib
Referenced from: /Users/blah/Library/R/4.0/library/kernlab/libs/kernlab.so
Reason: image not found
> detach("package:kernlab", unload = TRUE)
Error in detach("package:kernlab", unload = TRUE) :
invalid 'name' argument
I'm running on MacOS 11.2.3 and recently updated XCode (12.4) and CommandLineTools - this seemed to break a few things so I suspect there may be a connection. R is version 4.0.4 and RStudio is version 1.4.1106.
How do I go about trying to fix this?

Answer 1

I fixed this by using brew to uninstall R and Rstudio and reinstalling - but it only worked if I installed R from the cask, although the versions of R and RStudio remained the same.
The main difference I can see is that my new Makeconf file has a -mmacosx-version-min=10.13 flag set for CC, CXX, CXX11 etc (compiler is clang).