Your regex can't do that and it tries to use invalid syntax. You need to use this: Removing Unicode accentuation boils down to convert the string to norm form D (or KD) then remove all diacritic and/or modifier codepoints. In your case, removing combining diacritics works fine. ; Unicode Normalization Forms Global Enum $UNF_NormC = 1, $UNF_NormD, $UNF_NormKC = 5, $UNF_NormKD Func _UNF_Change($sIn, $iForm) If $iForm = $UNF_NormC Or $iForm = $UNF_NormD Or