[R-SIG-Mac] .libPaths

[Michael Hall]

I seem to have somehow changed this so that for install.packages my user location is always selected in preference to the system location.
Since I may at some point access packages from an application not connected to my user I would rather this not be the case. 
What I now get is…

.libPaths()
[1] "/Users/mjh/Library/R/3.4/library"                               "/Library/Frameworks/R.framework/Versions/3.4/Resources/library"
> install.packages("NOSUCH")
Installing package into ‘/Users/mjh/Library/R/3.4/library’
(as ‘lib’ is unspecified)
Warning message:
package ‘NOSUCH’ is not available (for R version 3.4.3) 

So everything is default installed into my user location. This didn’t used to be the case, but I do not remember what I may of done to permanently change it and so far I can’t figure out how to permanently undo it.
I have looked at the R Startup command, the OS X app preferences, OS X faq, environment variables, the system Resource folder, no .Rprofile is there and I didn’t figure out what be causing the setting in Renviron. 

How do I permanently remove the user directory from .libPaths?