Disable Subscription in vBulletin
 

Can I make the default Subscribe to Thread Option uncheck for my members so they can post without getting subscribed to threads?

Re: Disable Subscription in vBulletin
 

Yes you can do that.

For existing users you have to run a query.

vBulletin admincp > Maintenance > Execute SQL Query (You should have permission to execute SQL's in vBulletin) > Select Do not Subscribe for Automatic Query.

For new Users

vBulletin admincp > vBulletin Options > vBulletin Options > User registration Options > Default Registration Options > Automatic Thread Subscription Mode