I haven't been able to find any info on this so far, which is why I posted this curiosity and #f0dder: Many thanks for your helpful comments. What I would like to know is, if the mouse firmware has indeed been changed (as would seem to be the case, by deduction), then how can one revert/restore that firmware to its default initial state? Leaving the batteries out of the mouse for a while doesn't seem to do it. So, it seems that I may have just disabled 3 mice (or 2 at least), in testing out the Logitech pairing functionality. So, the unification seems to aggregate mice or other devices when it pairs, without discrimination, and it seems that the firmware within each mouse is changed on pairing, so THAT mouse can ONLY work through the unifying dongle, and henceforth THAT mouse cannot work through its original dongle as a 'Logitech HID-compliant cordless mouse'. I then re-pared the meece (using the Unifying software) to the M515 dongle. However, when I then tried to use M185 with its own dongle, it simply would not work. That seemed to work fine too, according to the UI report. The UI can display a report of the battery status (if the software can fetch the battery status) and the firmware version of each mouse paired. Then I installed it and, using the unifying software, paired the 3 meece to the M515 dongle. They used the USB device 'Logitech HID-compliant cordless mouse'.ДЄs M515 was a Unifying dongle, I downloaded the Unifying software from Logitech support. They all worked fine, separately, using their 3 separate, individual/unique dongles.

Using Win10 the other day, I experimentally took 3 meeces (Logitech M185, M215, M515). I wondered whether any DCF denizens could help to unravel a problem with this unifying process.

Logitech unifying software k270