One of the common issues I have faced several times regarding Virtualbox's shared folder, that is even though a shared folder connected to the virtual machine, it's not accessible.
means in some cases after connecting your shared folder to the Linux virtual machine, when you try to access its contents, it will deny the permission and show "The folder contents could not be displayed" message.
Open your Terminal. Type
sudo suthen enter your account password.
Write the following commands & execute it
sudo usermod -a -G vboxsf mir (*Instead of
mir use your account name)
sudo chown -R your_account_name:users /media/your_share_folder_name/
sudo chown -R mir:users /media/sf_Linux_Application/
3 . Now reboot your Virtual Machine and check the Shared Folder again.
Thanks for reading :)