Random crashes

The file I've attached crashes randomly. It might be when I click on something to perform an edit or during playback. This file was originally an orchestral piece written on version 3.6 (appimage on Linux, Zorin).
I'm in the process of creating a vocal arrangement with piano accompaniment. I've added SATB and piano parts above the score. The idea is to mute the orchestral parts while transcribing the piece to SATB and piano, and then deleting the orchestral parts when it's finished. I've used this method successfully in the past. However, using version 4.02 (again, appimage on Zorin), the file crashes randomly. I've enclosed what I've managed to do so far. This is a work in progress. Should I abandon it and use version 3.6 and, if I do, is there any way I can copy what I've done so far to save me doing it again?