I'm trying to edit a report or 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 reports in the same dataset, only the first person who opened a report can access the Calculations menu (). The other editor sees the message: This resource is locked because it is currently being edited by <name>.
Once the first person closes the report, the Calculations menu becomes available to the next editor. Additionally, to prevent conflicts, only one editor can edit the same report at a time.
For more information, see the article: Explore FAQ: Using Explore.