@Touchoco
Glad it works, but it's a shame to have to change over to 32-bit Qt app just to be able to talk ODBC to Excel.

If you want to pursue this further I think it is a non-Qt issue. You would have to Google for something about how to ODBC from a 64-bit executable when I have such-and-such (probably 32-bit) Excel, or similar.

Sorry for zombieing this one.
What that library does is loading all the data from the existing file and re-build it from scratch when you click save this means that any feature that existed in the original file but it's unsupported by the library will be removed on save just because the library doesn't even know they exist