Long time to load Rt on Win 10 64bit

Though this still doesn’t explain the problem if you’re using 4.2.1005.

Please explain again, in detail, what exactly happens the moment you click the RawTherapee shortcut. Do you see a window? Is it empty? How many thumbnails in your File Browser folder? Once RT loads, if you click the Preferences button, does that take a long time to open?