I can't make interface smaller

[smk2012_]

I made interface 200%, saved settings, and I didn't like it, I wanted to make it smaller, but Interface was too big for my 1920x1080 screen!

[Kayanor]

I made interface 200%, saved settings, and I didn't like it, I wanted to make it smaller, but Interface was too big for my 1920x1080 screen!

Go to your Factorio data (On Windows C:\Users\[Username]\AppData\Roaming\Factorio - Just enter %AppData% in the Run dialog) and go into the config directory. Delete the config.ini file there.
WARNING: All other configurations (keyboard, audio, ...) will get deleted, too!

Alternatively you can also open the file with a simple text editor like notepad and scroll down to system-ui-scale and change the value to "true" or set "1" (both without quotation marks) as value for custom-ui-scale.
The scaled up interface will change back to normal size.