Please avoid using 'Persist data' option in the app. There is a bug in Qt clipboard that clearing the data and accessing clipboard in quick succession causes the app to lose control over clipboard and it causes a deadlock. N9 intensifies the problem by auto clearing clipboard after every paste.

The deadlock happens generally after 3 quick pastes with persist ON. But sometimes it works fine.

Workaround, if you have persist on, try not to paste in quick succession. Give a few secs time between pastes