It's all about the Software

between a few Betas ago and Sept. 16, my unchanged hardware setup no longer is able to detect or use the RX888 Mk II.

log files seem interesting in that the RX888 is responding to probes and the responses look successful.
the unit serial number appears to be retrieved where, as best i can recall, before only a single (Cyrillic?) character would be shown.

three log files are attached: two attempts to start up using a pre-existing Radio Definition, and one attempt at searching for it in the hope of creating a new Radio Definition.

i note that prior to this Beta, when first plugged in, the RX888 is in bootloader mode. upon successful startup, the RX888 enters streaming mode and remains in that mode after the radio is stopped.

On a hunch, if you use it with other SDR programs unplug it and plug it back in again. The firmware load has to match what SDRC expects.
{^_^}

had to plug and unplug a few times to collect the log files.
thanks for the hunch, but i made sure to exercise all the possibilities before posting.

(back to edit a few minutes later) huh! left the thing un-powered overnight, plugged it back in, and now it's running.
what can i say? <shrug> gotta luv technology...

Thermal overload? Or it might be that the power supply capability of the USB port may be exceeded and the polyfuse was blown or partially blown (if that can happen.) That sounds a LOT like your case because it recovered with power off over night. I don't know what the power drain of an RX888 is. I do know it seemed to blow or damage one of my quad USB 3 cards. (While running it acted a lot like the USB was not QUITE up to the data transfer rate. Weak power could do that, I believe. If you can investigate how much power your USB 3 port can safely deliver. (My blown card claims 0.9 A per port as a baseline.)

{^_^}

might just be a timing thing when loading firmware.

i have a powered USB3 hub and have left RX888 plugged in for weeks at a time - firing up SDRC whenever i was moved to look at some spectrum or tune in a transmission.

this was the first time i ever had an impediment to that pattern of use.

I am runnin the RX888 from a USB 3.0 Hub, with channel knobs. Ocasionally it doeas not mount and I toggle the mount then. (Same on HSPDR). Please not i have opened the back of the device and blowing in air. If you dont ventilate, the device gets to HOT ! With cooling it runs at all frequencies stable.