Best to export from Excal as .txt. Then open in Encodinator to identify problems. Also, you can open in NotePad ++ and "Encode in UTF-8" to see where the problems are. Then search and replace these out in Excel .xlsx. Then export as Unicode. Then in Notepad ++ "Convert to ANSI", then reload into Encodinator and makes sure all is well. Then take that txt file in ANSI and "Convert to UTF-8" in NotePad ++. Then take it to Archivist Utility.