Macro to check for missing data and copy data if none missing

Okay. I have some code that loops through a column of data and pops up a message box if it finds an empty cell

Sub CheckDataEntered()

Sheets("Input Data").Select

        [c3].Select
            
        Do Until ActiveCell = ""
    
        ActiveCell.Offset(0, 1).Select
        
        Loop
        
            ActiveCell.Offset(0, -1).Select
       
        Do Until Selection.Row = 40
   
        If ActiveCell = "" Then

        MsgDataNotEntered

        Exit Do
        
        Else: ActiveCell.Offset(1, 0).Select
    
        End If
        
        Loop
        
End Sub

Clicking OK in the message box stops the code and tells the user that some data is missing. I have another macro (CopyData) that copies the data into another sheet. What I am trying to do is to get the CopyData macro to run in the above code. E.g. Check the column of data_if data is missing, stop all macros and show message box_if no data is missing, run CopyData macro. I hope this makes sense.

I tried to run this and got a compile error: sub or function not defined

All sorted. I changed:

:Err_End

to

Err_End:

Thank you very much, headache cleared