I have an .xla that was written on a 64-bit Windows computer running a 32-bit version of Excel. When I moved it to a 64-bit Windows computer running a 64-bit version of Excel, it would not run due to the Declare Functions. Using Microsoft's Code Inspector, an updated version for about half the Functions was suggested. The other half were commented by the Code Inspector as "NO EXACT MATCH". I was able to get these to work by changing any parameters that were passed ByVal and were of type Long to type LongPtr.
The .xla now runs fine in both environments, but it does not run--or I should say partially runs--on a Windows 64-bit computer with a 32-bit version of Excel 2016. By "partially runs" I mean there are no errors, but the add-in does not appear in the ribbon, and when I try to view the code, there is no code.
Confused and exhausted!