The first option works sudo mount -t vboxsf SHARENAME /media/vboxshared

1. create your shared folder at your PC. for example "c:\SharedBoth"
2. make sure you have selected your shared folder "c:\SharedBoth" at virtualbox menu "settings" - "shared folders" - "add" -"permanent/automount", before you start the ubuntu virtual machine.
3. start the ubuntu terminal, type in command above,
   sudo mount -t vboxsf SharedBoth /media
4. then check if folder sf_SharedBoth created in media folder Before you do the step 3, you need to make sure you have installed "guest addition"

sudo mount -t vboxsf SHARENAME /media/vboxshared 

1. create your shared folder at your PC. for example "c:\SharedBoth"
2. make sure you have selected your shared folder c:\SharedBoth at virtualbox menu "settings" - "shared folders" - "add" -"permanent/automount", before you start the ubuntu virtual machine.
3. start the ubuntu terminal, type in command above,
   sudo mount -t vboxsf SharedBoth /media
4. then check if folder sf_SharedBoth created in media folder Before you do the step 3, you need to make sure you have installed "guest additions"