Chapter 17 Advanced Troubleshooting R & RStudio Installation
For persistent issues you may need to try an older version of R. For Macs, download RSwitch from https://mac.r-project.org and an older version of R, https://cran.r-project.org/bin/macosx/R-3.3.3.pkg (Mac OS X 10.9 (Mavericks) and higher) or https://cran.r-project.org/bin/macosx/R-3.2.1-snowleopard.pkg (Mac OS X 10.6 (Snow Leopard) - 10.8 (Mountain Lion)). Unfortunately if you have to use older versions of R some new packages might not work; yeah…
For more advanced troubleshooting see https://support.rstudio.com/hc/en-us/articles/200488508-RStudio-Desktop-Will-Not-Start