Completed all steps to unlock achievement, but it didn't unlock.

Hi there! I'm more than happy to help you!

I'm sorry you are experiencing this with your Xbox achievements. No worries, let me help you sort this out.

Kindly try to perform the following workarounds:

1. Make sure that you're connected to the Xbox Network:

Make sure that your console is connected to your network equipment (such as router, modem, or gateway), and then press the Xbox button  to open the guide.
Select Profile & system > Settings > General > Network settings.
Verify that your console is connected to the network. If necessary, select Test network connection to get a diagnostic.

After connecting to the network, try unlocking the achievement again.

2. Check your achievement progress on your console:

When you unlock an achievement, you may not see a notification or an updated gamerscore right away. The Xbox service must validate your achievement first, which might cause a short delay.

If your Gamerscore isn’t updated online, verify that it's updated locally on your Xbox console.

After your gamerscore has updated on your console, verify that the changes have synchronized to the Xbox network. To see your achievements on your console:

Press the Xbox button  to open the guide.
Select Game activity > All achievements.

Select the game in which you unlocked the achievement, and then view the unlocked achievements list.

3. Check your achievement progress online:

You can check the progress of your achievement online to verify that your console has synchronized with the network.
To view your achievements 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 that you're trying to unlock.
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.

If the 72-hour time frame does not work, it would be best to reach out directly to the Game developer as they have the tools and resources to properly investigate this case.

You may also check this link for reference:

https://support.xbox.com/en-US/help...network, try unlocking the achievement again.

Thank you for your kindness and understanding! Please feel free to let me know if you need anything else.

Best Regards,
Darhyl

I didn't have problems with those achievements. I just played the campaign from start to finish and unlocked all of the campaign achievements. As far as the glitched achievement is concerned, it unlocks, but the reason it is glitched is because it unlocks
too early before completing all of the requirements.

I didn't enjoy it, but it's an easy completion if you're into achievements. It took me about 4 hours to unlock all of the achievements.

I think it's a bug. I had the same issue, i completed it on legendary co-op, got all the mission achievements but didn't get the achievement for completing the game on legendary and the first mission we started on didn't unlock.

The only achievement that is not unlocking right now is when you complete the first mission on Pillar of Autumn. Some achievements didn't unlock right way as well but they eventually popped up. I guess I'll have to wait till that one achievement unlocks
I guess?