There seems to be a strange bug in Rstudio preview 1.2.1244.
When attempting to open a file in Rstudio preview 1.2.1244 IDE in Windows 10, I get an error titles "Error while opening the file" with the text, "The system cannot find the file specified".
This occurs whether I open it from the file window, the file/open file menu, or even double clicking on the file in Windows Explorer (dragging doesn't do anything).
However, it only seems to happen in my user profile folder or its subfolders. When I open a file from a different location it works okay and if I copy a file from the profile folder to another folder it will open from the copy. Strangely, it will then also open the original file in the profile folder, but not other files that were not copied.
Can you elaborate on how you're opening these files? Are you opening them from within RStudio (using e.g. File -> Open File...) or by e.g. double-clicking those files from Windows Explorer or similar?
Does your user home folder have any non-ASCII characters (e.g. accented characters) or anything else unique?
I did a little experimentation and found that it only happens for files and folders in my home folder. It happens whether I try to load a file (or even change to a sub-folder) from the files window in RStudio, or if I double click on the file from Windows Explorer to launch in RStudio.
If I change my home folder by changing the environment variable, I can open files from the previous home folder, but not the new one.