I think I'd design tables in a separate db and import them as a way to avoid the potential for any corruption or design conflicts. However, I don't think that has anything to do with
when the user that did not create the access file tries to open the database, it is in read only mode.
State why you think it is read only. Prompts? There's a message at the very top indicating the db can't be modified?
This is on a network? No one is using a usb drive?
Is there a lock file in the folder where the db is kept? (.lccdb) when no one has it open?
Check Trusted Locations settings in options on the other person's pc.
I've never tried to share a db in the design phase so I could be wrong thinking that it's not a great idea if it's doable.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.