I used this process myself to good success under 10.12.5, on my Macbook Pro. TYPING THE COMMANDS WRONG MAY CAUSE SERIOUS ISSUES WITH YOUR MAC. DO NOT EXECUTE ANY OF THIS IF YOU ARE NOT SURE WHAT YOU ARE DOING AND DO NOT HAVE A BACKUP OF YOUR DATA. Obligatory warning: THIS IS MESSING WITH SYSTEM FILES. It will keep trying to refresh this cached data, and fail to do so. The issue is that there is an Apple Pay cache at /private/var/db/applepay/ on the system that has been invalidated, but it seems to be unable to delete this cache properly. If you try to do so by authorizing it using fingerprint or password, it will immediately drop you back to the original “Apple Pay is already configured on this disk for another Mac” prompt, going back into this cycle ad infinitum. The system will report “Apple Pay is already configured on this disk for another Mac” and ask you to “Reset Apple Pay and Add Card”.
If you recently had your Macbook Pro (Touch Bar) repaired (possibly with a logic board replacement), and restored from Time Machine backup, you might find yourself unable to use Apple Pay on Mac OS 10.12.5. Categories Solutions Resolving endless Apple Pay add card loop after Time Machine restore Unfortunately, this also means I cannot access Netflix anymore due to Netflix’s blocking of Hurricane Electric tunnels (as a “VPN”), but that’s another story for another time. Not sure if this is fragile or not, but I really only needed a temporary solution. With this “6rd” configuration active on the Netgear R7800, the tunnel appears to work, and I can once again access resources on IPv6 only servers. 6rd IPv4 Border Relay Address - Server IPv4 Address from tunnelbroker.
6rd Prefix - the Routed /48: value from tunnelbroker.Since I’m not a network engineer, I’m not 100% clear on why this works, or if there are any limitations to abusing the protocol this way, but it does appear to allow access to IPv6-only servers. The Netgear R7800 does not support 6in4 tunneling like the Apple AirPort Extreme, but it appears that its 6rd (IPv6 Rapid Deployment) mode can be used instead with. Note this is different from the 6to4 tunnel that is supported in the native Netgear R7800 firmware - a technology which seems to deprecated, if the repeatedly Google captchas and warnings were any indication.
It turns out that my Netgear Nighthawk X4S R7800 router (which itself was a replacement of a previous Netgear R7800 - long story with Asurion warranty insurance for another day) does not support 6in4 tunneling, which is the technology used in tunnelbroker. Namely, I opted to use Hurricane Electric’s IPv6 tunnel.
Thus, my fallback method was to use a tunnel broker to access IPv6 servers. Despite living in the SF Bay Area, nominally the tech capital of the US, my previous ISP did not support IPv6.