Losing Sound when Switching to Browser Mode (Mk1 Rack)

I'm running a non-powered Mk1 Rack (OS 13.05.61298), with Rig Manager (v3.10.13). All runs great in Performance Mode. When I switch to Browser Mode to check some different rigs in Rig Manager, I lose virtually all sound -- Just a whisper of signal which seems unrelated to any rig (it doesn't change at all changing rigs in Browser mode). I checked all cables and connections, tried different guitars, and rebooted a couple times ... no joy. On one reboot I went straight into Browser Mode and it worked for a bit then went bad again ... when I switch to Performance Mode all was fine. Doesn't matter what Rig I try in Browser mode. When I switch back to Performance Mode all is well (without rebooting).

Any thoughts from anyone? I have a backup I can install, but I've made a few tweaks in the last week on my Performance Rigs that I don't want to lose, so if there's something I can do short of a reinstall that would be great.

Thanks in advance.

I turned the Rack off for a bit and let it sit. I turned it on straight to Browser mode, and it worked for a bit. Then it lost tone again ... it's not losing 100% of the signal, but it's like it loses the Rig that's been selected and just gives out a very low generic signal. No selections or buttons affect this very low tone. I'm very puzzled.

well, in the absence of other thoughts I did a factory reset and then reinstalled my backup. So far it seems to work.