I was mid session and all my presets disappeared. So I opened IK Product Manager and saw that I needed an update. Ok, no big deal. Updated, Installed, Launch Amplitube 5, same situation.
They're all still in the preset folder under; IK Multimedia/AmpliTube 5/Presets/My Presets. I've moved them in and out of the preset folders that are still currently showing in the preset drop down, moved them to my desktop and back, lose in the preset folder, and back into the 'My Presets' folder I created for them. I've reinstalled twice after the update, restarted my computer after the update and twice after the problem persisted after each reinstall.
I'm not super distressed because I didn't lose any of my presets, but this does interfere with my current workflow heavily if the problem persists more than a day.