[stereocilia]

I think my controller is suddenly unable to communicate with anything.  In the controller under Settings > Advanced > Networking > Choose Network the Finding Networks function doesn't find mine or any of other seven networks at my neighbor's houses. 

My network name is still listed under Settings > Advanced > Diagnostics, but it can't ping, can't connect, etc.

Obviously, I can't play music, either.

I'll call customer support when they're open, but if anybody has an idea I'd love to hear it.

[holdent]

I just had a similar problem but with the receiver of my Duet.  The telephone support was excellent but it looks like the receiver is toast.  Some of the things they suggested was force a factory reset (I think that's what it was called); and remove the battery in the controller, count to ten and re-insert it.  They also asked if I had a spare SD card I could insert in the controller.  Unfortunately I didn't have one because I'd love to know what could be tested using it.

In the end nothing would work to resurrect the receiver and I had to send in for replacement.  This was a very painless process, they e-mailed a UPS label, and I took the Duet down to the local UPS shop and sent it off (no cost to me).  So far I've been very impresed with Logitech's customer service.

[stereocilia]

holdent, you called it.  Thank you.  It's fixed now.

The long version.  (reason for the delay: I decided not to tackle this until after I returned from a trip.)  Anyway,  tried removing the battery for a couple minutes, but that didn't work.  So,  I called Logitech support which was, as reported, excellent.  It turns out that a factory reset was all that was needed, and everything is up and running smoothly.  I thought that I had tried the factory reset by selecting it from the menu when it first happened, but maybe I did something wrong.  Instead, the service person told me to press the + and the "home" key at the same time at turn on to force a factory reset.  It found my network right after that. 

It's bizarre that it stopped working in the first place, but bonus points to Logitech for walking me through it.