This happened to me, moderating a server, while our only admin was on vacation.
I was able to remove "create thread" permissions from the default role, effectively turning threads off. But first I had to add a new role to grant myself those permissions. I also had to ask people who had created threads to please delete them because I still can't.
I was able to remove "create thread" permissions from the default role, effectively turning threads off. But first I had to add a new role to grant myself those permissions. I also had to ask people who had created threads to please delete them because I still can't.