Today the two-year-old TLS security certificate for cran.r-project.org expired, so suddenly in R you are getting errors running install.packages or update.packages.
The error looks like this:
--- Please select a CRAN mirror for use in this session ---
Error in download.file(url, destfile = f, quiet = TRUE) :
cannot open URL 'https://cran.r-project.org/CRAN_mirrors.csv'
In addition: Warning message:
In download.file(url, destfile = f, quiet = TRUE) :
InternetOpenUrl failed: 'The date in the certificate is invalid or has expired'
The workaround is simple: choose another repository! For example:
This is bad timing with the release of R 3.2.4 today. If you need to download R using your web browser, visit a mirror, such as cran.revolutionanalytics.com.
Tested with R 3.2.3 on Windows 7 and Windows Server 2012.