If I read manual (from Jan, 15, 2021) correcty, it says: ==== Perpetual session is very useful for working on a project over many days so you can just quit before shutting down and the next time you start up CINELERRA-GG you will be right back where you left off. You will retain all of your undo’s and redo’s. The binary file name is $HOME/.bcast5/perpetual.dat and as long as Settings → Preferences, the Appearance tab has the Flag Perpetual session set this capability takes effect. It is very important to understand that this is not the same as the continuously editing- operation-updated backup.xml file. The perpetual.dat file is only updated when you Quit CINELERRA-GG in the normal manner. Which means if you interrupt the program, or kill it, or there is a segv or system crash, the perpetual.dat file will only reflect the state of your project from when you last started CINELERRA-GG, and none of the editing/undo’s/redo’s you executed during the current session which was not ended normally. • the files backup.xml and backup.prev will operate the same as before so that if there is a crash, you will want to use File → Load backup in order to continue where you were interrupted. ==== So, I take this as IF my CinGG instance crashed with Perpetual Session turned on, I should start program again, load Backup, and then quit normally. So, on next load everything will by synced again. I am correct? Is there any pressure for making this Perpetual Session data also user-saveable? (I am thinking about another item in main menu, hidden if perpetual session turned off) Still thinking on automatic crash detection .... CinGG already know how to dump .dmp files so same function handle_dump() in guicast/bcsignals.C can be used to put crash file in ~/.bcast5, but this may become more complex with two or more instances .....