I was doing some improvements on my database and for some reason the monthly calendar starts with Wednesday now....
I dont know what I could have changed to mess it up.
Any ideas.
This is Filemaker version 8.5

Sounds like you may have deleted some of the interface records in the calendar: click the small "reset" button in the lower right of the about screen to fix this. If that fails, check the auto enter calc for the field "CalFilterStartWeekOnMondayGlob" and make sure this auto enter calc is defined as...

If(CalFilterStartWeekOnMondayGlob = "Yes";CalFilterStartWeekOnMondayGlob & "¶" & "1"; CalFilterStartWeekOnMondayGlob & "¶" & "0")

...and that the checkbox for "Do not replace existing..." is unchecked.

If that doesn't help, feel free to email me a copy of your file and I'll check it out.