The simple answer is that without an app or third party integration, you can’t conditionally prevent a status update.
However, there may be a workaround that will work for you. The following will change the {Item Status} column to “Not Done” if the user changes it to “Done” but the subitems are not all set to “Done”.
Create an additional status column {Subs Done} with “Yes” and “No”.
Setup these automations:
Hi Roxsie, I use subitems a lot and my advice would be instead of a typical status column, you set a status in the subitems and choose “show summary on parent item” in the settings. That way you’ll get a bar that fills up as the status’ are set as complete.
Then you could restrict the EDIT permissions on the parent item status column so that nobody could change the status manually. The only way it would be seen as “Done” is if all sub-items are marked as “Done” which would then trigger the automation