This is the regex I used to find all non-ascii characters "[^\x00-\x7f]" (everything in the double quotes) when I was searching in Excel.
The characters ranged from Chinese, non-printable, emoji, bullets, to MS Word smart quote characters.
Try to inspect Note content for non ascii characters that would cause Note conversion to fail and skip it so user knows to review those records. Give option in app to skip notes that may fail or attempt to convert anyways.
Per John Lee,
Try to inspect Note content for non ascii characters that would cause Note conversion to fail and skip it so user knows to review those records. Give option in app to skip notes that may fail or attempt to convert anyways.