MyError = WorksheetFunction.IsError(Range("A1"))

Public Function WorksheetErrors(ByRef Target As Range) As Boolean
  Dim rCell As Range
  Dim vErrorArray As Variant
  Dim iCounter As Integer

  vErrorArray = Array("#N/A", "#DIV/0!", "#NAME?", "#NULL!", "#NUM!",
"#REF!", "#VALUE!")
  Application.EnableEvents = False
  For iCounter = 0 To UBound(vErrorArray)
     With Target
        Set rCell = .Find(vErrorArray(iCounter), LookIn:=xlValues,
lookat:=xlWhole)
        If Not rCell Is Nothing Then
           WorksheetErrors = True
           Exit For
        End If
     End With
  Next

  Set rCell = Nothing
End Function

This checks to see what the formulas evaluate to:

Option Explicit
Sub testme()

   Dim TestRng As Range
   Dim wks As Worksheet
   
   Set wks = ActiveSheet
   With wks

       Set TestRng = Nothing
       On Error Resume Next
       Set TestRng = .Cells.SpecialCells(xlCellTypeFormulas, xlErrors)
       On Error GoTo 0
       
       If TestRng Is Nothing Then
           MsgBox "No errors in formulas!"
       Else
           MsgBox "You've got errors here: " & TestRng.Address(external:=True)
       End If
   End With
       
End Sub