I want to change my preferences, specifically the sketch directory, as the default path is write-protected for some reason. After looking on this forum, I understood that I need to change preferences.txt in Users/%username%/AppData/Arduino. But in AppData there is no Arduino folder. How can i fix this? Is there any way to change preferences without it?
By "the latest" do you mean 1.6.5r5?
Do you mean you don't have a folder named "C:\Users(username)\AppData\Roaming\Arduino15"?
You can set the sketch folder in the Preferences dialog, no need to edit preferences.txt.