Dear Mr.Michael Becker (@satikusala ),
Problems with exercises.
I started using your file as a reference for my daily study.
[TBX - L Managing Daily-Journal-Time-Projects-FINAL30JAN21.tbx]
Is it because of the compatibility of Tinderbox 9.6.1 version?
The Tinderbox.app shuts down every time when I write to somthing add it.
Is there any way to avoid this?
Previously, somewhere it was created with an earlier version of Tinderbox 9.6.1
I think there was a note about how to open the file.
Where was it written and how? I forgot to write it down.
Yours, WAKAMATSU
Wow! I’ve not touched that file for nearly two years now. 
I just opened it, and it opened fine.
Honestly, given how long ago I built this, I’m a bit nervous to see where I was and how far I’ve come since then (i.e., how much I did not know or understand back then; or at least could not effectively communicate).
If you hold the Shift key when you launch Tinderbox, this will keep TBX for opening previously opened files. You can then try to open it again,