Have been stuck on this problem for the past year or so and would really appreciate any help. I am unable to save any Rscripts in Rstudio, as I keep getting the first error above. The one exception is, when running Rstudio with administrative permissions, - when saving into C:/Users, which is apparently the default working directory. I am also able to open Rscripts from C:/Users, but not from anywhere else. When I change my working directory using setwd(), Rstudio accepts the change but I am unable to save or open files in the new directory (or anywhere else).
I have tried fully uninstalling and reinstalling Rstudio and R, as well as adding the folder R and Rstudio are in, and my desired working directory folder into the 'PATH' variable in windows (through 'edit the system environmental variables'). But nothing seems to be working. Have also searched online pretty extensively but haven't managed to find a working solution so far.
I am using the latest 2021.09.1 Build 372 of Rstudio, and R 4.0.4. However, I have also faced the same problem on the last few versions of Rstudio and R over the past year as I have tried to update hoping that it would fix the problem but to no avail. I downloaded R and Rstudio from CRAN and the Rstudio website respectively.
Thanks a lot!