I shut off some breakers to install a ZWave dimmer switch and consequently powered off the EISY. After I got the switch installed and turned the breaker back on, the EISY came back up, but in the console under ZWave, it said something like "ZWave Radio Not Available". 

It did not change after rebooting the EISY both from the command line (I'm a Linux sysadmin, so I'm pretty comfortable there) and via the console. So I disabled ZWave under Configuration > System, rebooted and re-enabled it. 

Now it's been repeatedly popping up the "system busy" dialog with a status that goes up to 100%, taking about 10 minutes to do so and keeps repeating. I think it's done that 4 or 5 times so far. I only have 3 ZWave devices in my network so far, the dimmer would be #4. 

It just completed again and started over. 

What is it doing and how many times will it do it? Is there anything else I should do if the EISY loses power then says the ZWave radio is unavailable? 

Have you tried unplugging the Zmatter/zwave dongle from the eisy then plugging it back in while the eisy is powered up.  It's possible that the usb port is not seeing the dongle.

Yeah, I tried that once... will try again. I went out and did errands, and it's still got the "system busy" thing. 

I'm also considering just doing a full reset on the EISY. I've got a lot of stuff from my old house that will have to be altered manually... I'm thinking rebuilding might be cleaner. 

 

Ok, so I pulled the dongle entirely out and rebooted, then saw the error that the radio was not responding. Expected. Then I plugged it into a different port on the side of the EISY and rebooted again. Now it comes up and I'm able to add the switch I installed. Let's see if it finishes. If it does and it works, I might just delete most of my programs and variables instead of doing a complete nuke & pave.