Strangely enough, I got a message that I would convert ‘png’ into ‘mov’.
I think it’s because we didn’t import the png file and we dragged it into the project.
After trying many ways to open library on the Internet, I saved the library.
It’s not perfect, but it’s not hard to work.
I don’t think there are many, but I write down the methods I used for people with problems like myself.
1.I’m going to look at the hidden files in the library.
2.Delete the currentversion.flexible.
3.I opened it in the final cut X of the version before the update
->Although it damaged, I finally opened the library.
4.I opened the backed up library, exported it to the xml of each project.
5.I created a new library, and saved it.
Thank you Ronny for answering my question.