error mounting guest additions ISO in Virtualbox 6.1.4 and 6.1.2
In VirtualBox 6.1.4 and 6.1.2 is the same error after choosing Devices->Insert Guest Additions CD image... in VirtualBox virtual machine pull-down menu: Error in mounting /dev/sr0 at /media/student/VBox_GAS_6.1.4: wrong fs type, bad option, bad superblock on /dev/sr0, missing codepage or helper program, or other error. Same error when trying to mount in graphical file manager Caja. When mounting at command-line there is no problem. Earlier time there was no problem also with graphical mount. Host and guest: 64-bit Linux Mint 19.3 MATE with all current updates. When 6.1.4 came out, hoped that this is fixed but it seems like not.