I"m having the same problem.   And the answer that was provided by QB saying it is solved is wrong.   I can prove it because i tried to re-import a file that i did last week successfully and it doesn't work this week - SAME FILE.   So something has changed on the QB side.   The stupid answer that they gave to use csv is ridiculous.  it's too much work to reform dates, combine columns, and then all the rules won't work because the import is different.   Someone at Intuit needs to find out what changed in the last week.  They either support QBO or they don't.