I have 2 achievements that will not unlock for me in assassins creed IV. They are "Barfly"...

I'm also having the same problem. I'm not unlocking any achievements for my Assassins's Creed IV Black Flag game. I've doe 20 different swinging rope assassinations for an achievement, but the achievement is still stuck at 60%.

I had the same thing 2 days ago with Advanced Warfare and Assassins Creed Unity. All but one of the Assassins Creed achievements has unlocked.

Mine has now started working again but not properly, the story progression achievments wont unlock for assassins creed: ezio collection ive done the first 3 sequences of AC2 and they havent unlocked

Hi, I hope you're doing great out there. I am an Independent advisor and I am here to help you in regard to your concern.

According to Xbox support:

"If a completed achievement hasn't appeared online after 72 hours, your console might not be connected to the Xbox network. If you completed an achievement or challenge while offline, you won't receive related notices or rewards until you connect to the Xbox network."

Kindly perform an extended powercycle and reset your network hardware by following the steps below:

1. Unplug the power cable from the back of the router, modem, or gateway for 5 minutes. If you have a router and a modem, unplug the power cable from both devices.

2. Press and hold the Xbox button on your console for 10 seconds or until it turns off then wait for 2 minutes before turning it on again.

3. After 5 minutes, plug the modem or gateway in first, and wait for all the lights to return to their normal state.

4. If you are using a router, plug in the router and wait for all the lights to return to their normal state.

For your reference, you can check this link: https://support.xbox.com/en-US/help/games-apps/...

Not just you mate. I have only completed 2 of the legendary ships so hopefully it will unlock for me. but I've done Barfly, Sea Legs and Siren Song yesterday and not one unlocked.

I didn't have an issue with Watch_Dogs I've unlocked all of them with out a hitch. I had a similar issue on Titan Fall, but 2 days later they popped up as unlocked while on the home screen.

it doesn't seem game specific it seems like the achievement system it self.