This will walk you through how to get 64-bit Excel working and how to fix the issue where the integration stops working. 

First, go to where the dll files are saved: this should be something like C:\User\"userName"\AppData\Roaming\Microsoft\AddIns.

If you don't have the dll files, they are attached at the bottom of this article; make sure you grab the right ones for your Excel. You will need to put them in this location: C:\Users\"userName"\AppData\Roaming\Microsoft\AddIns.

Rename the swiftxl9.dll to have a space before the 9, so it is like this: swiftxl 9.dll.  

Now register the dlls using cmd.

Launch cmd in admin mode and enter:

        cd C:\Users\"userName"\AppData\Roaming\Microsoft\AddIns  

Press Enter and run this command:

       regsvr32 psconnector9.dll   

Now run this command:

       regsvr32 "swiftxl 9.dll"   

That should resolve the issue.