Just downloaded the launcher and tried installing 3.5. It downloaded a 13GB file (Data.p4k) and then stopped and just showed the Install button again. Clicking this does nothing, a progress bar briefly flicks up and then back to Install button. Note that this also happened to me when I tried to install 3.4. I've tried uninstalling, deleting files and folders etc. I has probably been 3 months since I was last able to play and I assumed 3.5 release would fix the issue. Edit: SOLUTION (for me) - Problem was my drive being exFAT and the fix was to change that to NTFS.