Applies to- Mac only.
Solution-
- Quit QuarkXPress 2018 Pro (if opened).
- Navigate to Go menu (Desktop) >> (Press and hold down the option/alt key) Library >> Containers >> com.quark.QuarkXPress 2018.pro >> Data >> Library >> Preferences >> Quark
- Under Quark, rename the folder named "QuarkXPress 2018" to "Old_QuarkXPress 2018".