This also worked for me ...

We recently upgraded to Office 365 (64 bit) and I could no longer import Excel files in either SSMS 2014 or SSMS v17.9.1.  Yet after...

Also, once failures are found, you could distinguish actual '?' values from Unicode values and get the percentage of Unicode characters with ...

SELECT t.val

, UnicodeStringLen = len(t.val)

...