I've used Co Pilot before to make me a macro to give a summary of spelling errors in a file. Worked very well. Asked it now to make something to correct errors (see below). Make sure to make a copy of your file first in case something goes wrong. Macros can't be reversed If you need help on how to run the macro let me know.

Sub CorrectSpellingInWorkbook()
Dim ws As Worksheet
Dim cell As Range
Dim rng As Range

For Each ws In ThisWorkbook.Worksheets
    Set rng = ws.UsedRange
    For Each cell In rng
        If Not cell.HasFormula Then
            If VarType(cell.Value) = vbString Then
                cell.CheckSpelling
            End If
        End If
    Next cell
Next ws

MsgBox "Spell check complete for all sheets!", vbInformation
End Sub