Sorry I posted the wrong half of the code:

Here what I want to change:

Sub Time_Load_Extension_Displacement_Mac()

Answer = MsgBox("Did you select Time,Load, Machine Extension & Displacement on the tensile machine, when you exported the data?", vbQuestion + vbYesNo + vbDefaultButton2, "Alert")


If Answer = vbNo Then Exit Sub

MsgBox ("Select your file")

With Application.FileDialog(msoFileDialogFilePicker)
'Makes sure the user can select only one file
.AllowMultiSelect = True
.Show

'Store in fullpath variable
fullpath = .SelectedItems.Item(1)
End With

'It's a good idea to still check if the file type selected is accurate.
'Quit the procedure if the user didn't select the type of file we need.
If InStr(fullpath, ".txt") = 0 Then
Exit Sub
End If

'Open the file selected by the user
Workbooks.Open fullpath

ActiveSheet.Columns.AutoFit


'Construct graphical analysis