I am trying to update my HP Prime calculator and I'm having the same problem. My software version is 2013 11 25 (5447) and I am using Mac OS10.14.6 (Mojave) and the connectivity kit downloaded from HP USA just 09/12/19 (today).
With the HP Prime connected to my Mac using a USB cable, the Connectivity Kit does not recognize the calculator.
Sorry... but I'm not that experienced with discussion groups... I did some noodling around and found the following post that solved the problem for me. To summarize, I had an old version of firmware on my Hp Prime that did not work with the Mac version of the Connectivity Kit so I had to use the Windows version to update the firmware, after updating I was able to connect using the Mac version. Thanks to anyone who helped with this!
This is from Tim_Wessman...
The issue here is that the calculator is quite old and there are 2 posible problems preventing it from connecting. One was a problem with on a USB 3 port that made it not be recognized when switching from "normal" mode into "update" mode. The other has to do with the old version of the software needing to be updated first before connecting to the latest connkit.
This procedure should let you get up and running. Note - the windows connkit will be needed here. The Mac does not allow updating a unit with this very old firmware. Once you have updated, all future updates will work fine from the Mac.
1. Put that calculator into the "recovery mode". Don't have it connected yet. To do this, hold down the SYMB key and then power on the unit. It should now say "recovery mode".
2. Now plug it in. Preferably, into a port that you haven't used before to connect with, or a USB 2 port. This can prevent windows from getting confused about the driver to load for the device.
3. Start the latest version of the connkit. It should have downloaded previously the latest version of the files and they should be in "<your documents>/HP Connectivity Kit/Firmware". If not, let it download now. If it downloads, close the connkit and reopen it.
4. A window prompting you to update should come up. Let it proceed, and you should be good.
If there are any problems, post back here and we will get through it. Thanks!