A previous suggestion by Bill Manville:
There is no built-in way to get a flashing colour.
If it is a particular cell that you want to test, try something like this>
Here's one way. Just select colour 10 for the font of the cells you want to
flash. Unfortunately the whole screen is
redrawn so the cell flashing is not as significant as you would like:
Dim NextTime As Date
Sub Flash()
If ActiveWorkbook.Colors(10) = RGB(255, 0, 0) Then
ActiveWorkbook.Colors(10) = RGB(0, 255, 0)
Else
ActiveWorkbook.Colors(10) = RGB(255, 0, 0)
End If
NextTime = Now + TimeValue("00:00:01")
Application.OnTime NextTime, "Flash"
End Sub
Sub Auto_Close()
Application.OnTime NextTime, "Flash", schedule:=False
End Sub