VBA For Changing 2 to a Superscript when it's in a defined string

Question

so I tried to create a code just to do some basic formatting in the headers of long data sets. I have a fixsymbol code to change the um to micrometers with the proper symbol but when I try to run the code below to change the (um2) to a superscript 2 it flashes Error 13 type mismatch and the debug highlights this line "Position = InStr(c.Value, "µm2")" It still runs the code but spits the error at the end and if I try to run it on a raw data set not in a table it crashes Excel. How would I fix this error so I can have it run as a part of a larger script without crashing?

Sub ChangeToSuperScript()
Dim X As Long
Dim Position As Long
Dim c As Range
For Each c In Range("A:Z") 'range of cells
Position = InStr(c.Value, "µm2") 'change the number 2 into a potentiation sign
If Position Then c.Characters(Position + 2, 1).Font.Superscript = True
Next
End Sub

Thanks!

Answer 1

You can screen out error values.

EDIT: updated to use SpecialCells to only operate on fixed values...

Sub ChangeToSuperScript()

    Dim ws As Worksheet, rng As Range
    Dim Position As Long, c As Range
    
    Set ws = ActiveSheet
    On Error Resume Next 'ignore error if no constants
    Set rng = ws.Cells.SpecialCells(xlCellTypeConstants)
    On Error GoTo 0      'stop ignoring errors
    If rng Is Nothing Then Exit Sub 'no fixed values
    
    On Error GoTo haveError
    Application.Calculation = xlCalculationManual
    For Each c In rng.Cells
        Position = InStr(c.Value, "µm2")
        Debug.Print c.Address, c.Value, Position
        If Position > 0 Then
            c.Characters(Position + 2, 1).Font.Superscript = True
        End If
    Next
    Application.Calculation = xlCalculationAutomatic
    Exit Sub
    
haveError:
    Debug.Print "Error:" & Err.Description
    Application.Calculation = xlCalculationAutomatic

End Sub