Set bars in system

Hi,

Please tell me how I can set the bars to 4 per system.
What worked in other instances, but is not working this time:
Format / Add/Remove System Breaks*

Possible reason that it isn't working: There are too many notes (16th notes / 16th-note rests) in the bars which I want to set as a 4-bar system.

Is there any other way to create a 4-bar system - other than the steps above?*

See image / file if necessary