# Diacritical Characters in Unicode

The OCVMax tool does not support the use of any 'combining' characters, such as Unicode combining diacritical characters. The OCVMax tool assumes that each character position is associated with a single character code or Unicode 'code point'. If you need to verify characters with diacritical marks, use a precomposed Unicode character code. You can use the .NET System.String.Normalize method with the System.String.NormalizationForm.FormC normalization form to preprocess strings that contain unicode combining characters.