I'm trying to edit a query or to access the Explore calculations menu and I see this message: This resource is locked. What's the problem?
If two editors are creating or editing different queries in the same dataset, only the first person who opened a query can access the Calculations menu (). The other editor will see the message: This resource is locked because it is currently being edited by <name>.
Once the first person closes the query, the Calculations menu will become available to the next editor. Additionally, to prevent conflicts, only one editor can edit the same query at a time.
For more information, see the article: Explore FAQ: Using Explore.