参考:https://blog.csdn.net/h66295112/article/details/81085643
参考:https://askubuntu.com/questions/71708/how-do-i-open-access-your-private-data-desktop
原因应该是通过terminal修改了ubuntu密码，然后重启
cpp
THIS DIRECTORY HAS BEEN UNMOUNTED TO PROTECT YOUR DATA.
From the graphical desktop, click on:
"Access Your Private Data"
or
From the command line, run:
ecryptfs-mount-private 8
You are trying to access data from an encrypted directory. To do this, log in as the user owning the data in question (eg sally for /home/sally). If the home directory itself is encrypted, logging in will automatically decrypt the data. If it is a Private directory, there should be a launcher in that folder to click (which may again prompt you for the user password).
If the "Access Your Private Data" launcher fails for some reason, use this command and follow instructions:
cpp
ecryptfs-mount-privateIf, for some reason, you have the data in question independent of the system it was used in, you will need the private key that Ubuntu's encryption wizard asked you to save on installation.
If you have neither the password for user with that encrypted directory, nor the private key, I'm afraid there is no way to recover the data.
打开README.txt,提示输入ecryptfs-mount-private，需要退到/home目录下，该目录下有个隐藏文件夹 ./ecryptfs,然后输入ecryptfs-mount-private，输入以前的密码，就ok了，具体的原因正在积极查找中