Then make message 1
The virtual file system (VFS) has been created with a newer version of HFS. Some data was discarded because it is unknown.
the reference to VFS is now included in the title, isn't it enough?
and why remove the last sentence? it warns people about losing data, i think it is quite important
and message 2
Because of the problems encountered in loading the VFS, automatic saving has been disabled. To correct this problem, save your file system manually from the menu.
Is that better?
this way people will think saving is a solution with no drawbacks. it is not true, they will probably lose data doing so. if it is not a problem to lose data, i will just make HFS not disable the automatic saving instead of bothering the user.
anyway, newer versions will display message2 only if any autosaving feature is enabled