Yesterday I installed Linux I liked how it works on my computer, everything was fine until the need to turn off the computer because when I turned off and on all my pictures, my music were missing any changes to do after you reset or unplugged again to the same....
The problem might be because you are using guest account. Ubuntu's Guest account is a special type of account, which has its home directory set to the mount point of a
tmpfs filesystem, which is used to store data which does not need to be persisted after a reboot.
The data in
tmpfs is stored in
RAM backed up by the
swap space, so it is likely the data had never been written to disk in the first place, so there's basically nothing to recover.
More details on tmpfs.
If you're curious how guest account is set up, you can study /usr/sbin/guest-account, which is a shell script used to create/remove a guest account.
Answer from here