I recently bought a Microsoft Surface Ergonomic keyboard. It paired with my mid 2011 MacBook Air running High Sierra straight away. However, when I try to pair it with my mid 2011 iMac (also running High Sierra) it just won't pair. It occasionally recognises a new device, although the MacBook picked up immediately that it was an 'ergonomic keyboard,' when the iMac recognises it it identifies it as unknown device with a serial number 00-00-00-00-00. It then asked me to enter a code, I've tried the generic 0000 as well as 1234, and even 00-00-00-00-00, but it continually fails to connect.
I've also tried - and failed- to use the 'set up a new keyboard' function in Bluetooth preferences. That button only appears sporadically, but when it has I've tried to 'press the button that appears to the left of the shift key' to identify the keyboard, but this doesn't work either.
I've about come to the end of ideas, anyone out there have a similar experience and managed to find a solution? Grateful for any help received.