Ok lets try this, download the last FW update from the web site and unpack the zip file.
Use IE or FF only, and disable any 3rd party browser add-ons and disable security SW on the PC.
Disconnect all devices accept the wired PC. Including the ISP modem. Will connect the ISP modem later. Just test with out it for now.
Factory reset the router using the UI or the button.
Reload the FW file.
Factory reset once more after the FW was processed.
Set up the router from scratch.
Set single mode N on both radios and give separate SSID names for each radio.
Set Open security on WiFi temporarily. Will enable WPA2 later.
Set up a reserved IP address for the wired PC.
Turn on the MBP and see if it connects. If so, give a reserved IP address and save settings.
Reboot the router with the PC.
Place the MBP into QoS at a high or low section.
Place the PC into the high or highest section.
Anything happen using this process up to this point?
If the problem still happens here then I'm thinking the router needs to be RMAd.
Let us know...
Sorry, I wasn't being notified of these posts. I gave up. Contacted D-Link call centre many times and L1/L2 just fumble around uselessly. I get told they have to escalate it to level nth and nobody ever calls back. Rinse and repeat. All relevant info is in this thread already I think.
My MBP works fine on AC5ghz, as does my Galaxy S5. Then I implement QOS for any device (I want a Windows PC to have priority). I boot up my MBP, it tries to connect, then we get a crash/boot cycle on the router.