Finally got it running. Set it up as a media server as a test instead of bothering with the Time Machine web interface options and was able to see and access the drive including TM setup from my Mac.
Not sure what the problem was, but I simply erased and reformatted the drive Mac OS X Extended and it is now showing up properly in the router web interface. However I'm not able to see it on my Mac during TM setup or via SMB (same error as before). Any suggestions?
Been working to set up time machine on since I bought this router without success. Have a 2TB WD My Passport Ultra that I was successfully using with an old Airport for a long time without issue. On the AC68U I can only see what is presumably the wrong partition (sda3) with a total space of just...