Any reason you are not just formatting the Cell and using the TextBoxes' ControlSource Property?

Have you tried using 
Cell = NumberFormat(Me.Currdate.Text),"YYYY-MM-DD")
What is the actual output of the 
MsgBox Me.DatePicker
and of 
MsgBox Me.Currdate.text
Can you format the output of the DatePicker? Are they compatible with Format or NumberFormat?

Have you checked his workbooks Date1904 Property?

How about language settings incompatibilities?