I just archived a project, but it looks like the tasks with assignees and dates keep showing in the calendar and my tasks area and searches.
I read a topic here about shift clicking the first task and selecting the others, but we use the board feature, so I don’t think this is possible.
How can I solve this?
Archiving a project removes it from the left sidebar list and from search results, but it doesn’t actually change the individual tasks in the project. If you need to multiple-select tasks to change them (like remove the assignees and due dates or delete the tasks), you can use Advanced Search to find all the tasks (or the completed tasks, or the incomplete tasks, or the tasks with certain due dates) just in that one project. The search results will essentially act as the List version of the Board project, albeit without columns/sections.
Here’s more on archiving projects: