Yesterday my machine updated Windows 11 with the January 2025 Windows patch 24H2. Today, while trying to open RStudio, my machine is asking me to select an 'existing installation'. It lists the installations on my machine with the directory path C:\Program Files\R\R... but when I try to select any install I get the warning "An error occurred while attempting to load the selected version of R. Please select a different R installation."
I tried running the R.exe in the command terminal and nothing happens. I tried selecting the R.exe and nothing happened. In the terminal I run 'cd C:\Program Files\R\R-4.4.2\bin' to set my working directory. I then run 'R.exe' and the terminal reports "Fatal error: 'R_TempDir' contains space"
EDIT: It was necessary to run the executable as Administrator. I think the update may have removed this default setting. So I navigated to the executable, which for my install was 'C:\Program Files\R\R-4.4.2\bin\R.exe', right clicked, and selected 'Run as administrator' and that then seems to have allowed R to start in the console and if trying to run from RStudio, it no longer asks me to select a version and then throws an error. Trial and error got me there. I did not find any information on this online. Maybe it is an expectation with respect to using Windows, rather than R and RStudio. I hope this is helpful to someone.