Solution:
1. Find those missing files and delete them.
In/private/var/mobile/media/itunes _ control/music, there is a F00-f11* *12 folder. Whether it is audio or video, the file name has changed after it is put in, but it can be found by synchronization time or file size. The lost files are also in these folders, so how to enter the folders is not specific. Winscp and 9 1 will do. It should be noted that it is necessary to determine whether the video or audio to be deleted is lost. You can copy the file to your PC and open it to make sure it is clear.
2. File management programs, map programs, dictionary programs and book programs all consume other capacities. What we need to do is to calculate the file capacity in these programs and whether it is consistent with other added capacities. If you don't want these files or books, please clean them up frequently and delete unnecessary dictionaries, map caches and unnecessary files.