I am a little confused - this post is not that old - but nothing from the QB support?  I just purchased QB Desktop for Mac 2019.  I am BRAND NEW to the QB application and need to import only six months of check transactions that are in an EXCEL /CSV  format.  In the QB fDesktop for Mac 2019, there is a very straightforward approach to importing check data.  Literally for the file menu, the path is IMPORT -> TRANSACTIONS -> CHECKS.  This selection allows you to copy and paste your information into a form with field headers.  moving your columns around in EXCEL, would allow you to simple copy and paste.  How is no one from the QB support staff able to reference this on these posts?  My reason for replying is that I took a conservative approach to import data - brought in a few hundred transactions and things were golden - yahoo!  Then I wrote/printed my first check with QB - things went as expected, but now the import function will not import my check number?  

Not sure which version, you are using, but the concept of importing simple CSV or tab-delimited info is there without using WebConnect or IIF - I just do not think QB support knows about it or is able to explain.