I got a problem with the save as location as when I click Open File Dialog, it take me to C:/Users/Windows/System32 as the default location. Last time it was Desktop but since I change the project folder location, it change location as well. How do I change the default save as location as I desired?

Have you looked in Menu > Settings > Configure Kdenlive?

Project Defaults and Environment tabs allow to set default folders (among other things).

Which option should I look at? I know Project Defaults is only where they keep the project folders

If it's not there then I am afraid you cannot define it. Could it be that kdenlive remembers the last folder you used in any of the file operations (open, save, save as)?

No, I last used the folder I usually save the render videos but it always take me back to the System32 location