MS Project Standard 2021 calculating duration incorrectly

Hi anjseattle 

As Dale pointed out, you most likely have 8 hours in the Hours per week option of your project.

If so, I recommend that you follow the following steps to avoid losing part of your work, if the values shown in the Duration column, at the task level not summary task, are correct:

1. In the tasks table, clear all active filters and expand all summary tasks.
2. Select and Copy the Duration column (to clipboard)
3. Change to 40 hours, the Hours per week option for your project.
4. Paste the Duration column.
5. Put all tasks in Auto Scheduled Task Mode.

N.- The final result of the dates will depend on the different restrictions of the Finish no Earlier Than type, which apparently many of the tasks shown in your screenshot have. I remind you that one of the ways to eliminate them is to leave Type in As Soon As Possible.

I hope you find it useful.

Ignacio Martín