Why is my achievement not unlocking even though I completed it?

Hi, Connor. I hope you're doing well and safe out there. I'm an Independent Advisor and I’m happy to help you today.

Kindly check if your achievement is already completed online. Sign in at Xbox.com.

Select your profile icon in the upper-right corner, and then select Xbox profile > Achievements. Select the title of the achievement, if the achievement appears under Achievements, it's already unlocked. If the achievement appears under “Locked Achievements,” either the achievement was not successfully unlocked, or the console hasn’t synchronized with the Xbox network. Allow up to 72 hours for this synchronization to take place. If it hasn't appeared after 72 hours, try unlocking the achievement again.

You can also try restarting your console as advised here: https://support.xbox.com/en-US/help/games-apps/....

my diablo 3 achievements for Above & Beyond and trade in didn't unlock for me. it shows that they are completed but are still locked. hopefully they will unlock when i get on later today to play. after the alert was over i did get two more achievements,
but these two are still locked even though they are shown to be completed.

It helped and now I'm able to get the achievements. Well one is still not unlocking even though it says I completed it. The "Welcome to horde mode" achievement seems to be stuck even though It shows I did it on the awards and stats page in the GOW3 menu.

I have over twenty achievements that I cannot unlock, even though several of them say I have 100% completion. I have achievements not being unlocked in Murdered: Soul Suspect, Crimson Dragon, and Strike Suit Zero.

I have the same problem with "One Shall Stand, One Shall Fall" not unlocking even though I completed the follow-up achievement. In addition the achievement progress is stuck at 0 percent for all achievements even though they unlock when I reach the correct
number. It's the only game where this happens for me all others track achievement progress correctly. I am not in the mood to start a new save and play the story again just for the achievement.