>Hi Cetin,
>
>Set Sysformats was on. But setting it Off doesn't seem to change anything. I still can't intercept the .Value in .Valid or Lostfocus Events. Then the app quits with no message.

Christian,
If I'm not wrong Set Sysformats are scoped to current datasession. Set it to off explicitly in form's datasession (DE.Beforeopentables,load,init etc).
Next if it still goes simply shutting the VFP down then suspect underlying code. Otherwise dates from {^0100/01/01} to {^9999/12/31} in VFP's range (unlike many Activex's if you have one).
Cetin