The 2017-10-10 security patch from Microsoft unexpectedly impacted the Jet driver and 64-bit versions of the Access drivers. These drivers now have issues reading in certain data types. The following Windows versions were impacted:
Basically, the Jet driver can't tell the difference between some data types, and it is trying to mismatch them.
Those match, right? Totally the same thing
But I can still access .xls...?
That's great! That means you are either on a version that wasn't impacted or you didn't install the patch. If that's the case, just don't install that patch until this gets resolved!
Well, I'm on one of those AND I have the patch. What do I have to do?
Head over to this page and install the 32-bit 2010 Access driver. Be sure to install the 32-bit version, because it matches the behavior of the pre-patch Jet driver perfectly. In fact, it matches so perfectly, we don't even check for the 64-bit version!
Once 11.7 is release, install the new Designer and start accessing those .xls files again!