I use sequencer to animate metahuman face with face controls(linked level sequence ), when I press the save button in sequencer UI to save current change, the UI get stuck for about one minute, it will save successfully, just takes too long to save.
In my case, the problem disappeared without me realizing it (I moved from a regular external hard drive to an SSD), but here’s the workaround I used at the time. After closing Sequencer, I right-clicked Save Sequencer in the Content Browser and it saved immediately.