详细错误：
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel modules. This may take a while. VirtualBox Guest Additions: To build modules for other installed kernels, run VirtualBox Guest Additions: /sbin/rcvboxadd quicksetup <version> VirtualBox Guest Additions: or VirtualBox Guest Additions: /sbin/rcvboxadd quicksetup all VirtualBox Guest Additions: Building the modules for kernel 4.4.131-20200710.kylin.x86-generic. VirtualBox Guest Additions: Look at /var/log/vboxadd-setup.log to find out what went wrong update-initramfs: Generating /boot/initrd.img-4.4.131-20200710.kylin.x86-generic Adding IMA binaries W: plymouth module (/usr/lib/x86_64-linux-gnu/plymouth//ubuntu-text.so) missing, skipping that theme. SELinux: Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version. SELinux: Could not open policy file <= /etc/selinux/targeted/policy/policy.29: No such file or directory /sbin/load_policy: Can't load policy: No such file or directory libsemanage.semanage_reload_policy: load_policy returned error code 2. SELinux: Could not downgrade policy file /etc/selinux/targeted/policy/policy.29, searching for an older version. SELinux: Could not open policy file <= /etc/selinux/targeted/policy/policy.29: No such file or directory /sbin/load_policy: Can't load policy: No such file or directory libsemanage.semanage_reload_policy: load_policy returned error code 2. OSError: Error VirtualBox Guest Additions: Running kernel modules will not be replaced until the system is restarted
解决办法：
$ sestatus SELinux status: disabled $ getenforce Disabled # 有的系统，文件是：/etc/sysconfig/selinux sudo vi /etc/selinux/config SELINUX=enforcing # enforce
重启后还是无法安装。
