BP V7 process hangs on Attach and sticks in Warning state

Since moving to BP V7 we have has significant problems with processes becoming stuck at the Attach stage, and then going to Warning in the Control Room. In some cases they don’t error or fail, the process does not terminate so we have to log in and force the process offline before we can restart it. Over the last couple of weeks we have found several common triggers and you should consider each of these.