UPDATE Also see this stack overflow post at https://stackoverflow.com/questions/46590002/warning-in-install-packages-unable-to-move-temporary-installation - Open McAfee Endpoint Security on your computer - Click on THREAT PREVENTION - Scroll down a little and unselect (turn off) Enable On-Access Scan
During your active RStudio session, at the command prompt you can run:
When the editing window pops up, scroll to line 142 and change
Click SAVE. This fixes the read/write time issue - BUT ONLY FOR THIS RSTUDIO SESSION YES, you will need to run during each RStudio session when you need to install new packages.