I don't see any reason why it would lock up with more than 20 cells, but you
could change the code to something like:

Sub Add_ed1()
Dim cell As Range
Application.ScreenUpdating = False
For Each cell In Selection.cells
cell.Value = cell.Value & "_ed1"
Next 'cell
Application.ScreenUpdating = True
End Sub

rblivewire wrote:

What do I change to make it at the users selection which cells to
change? Also, do you know why it keeps locking up everytime I run it
for more than 20 cells?

--

Dave Peterson