Cannot mount Guest additions disk image

Discussions related to using VirtualBox on Mac OS X hosts.
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macandroid
Posts: 27
Joined: 10. Nov 2018, 14:04

Cannot mount Guest additions disk image

Post by macandroid »

I have Centos 7 running as guest on macOS 15.5 Catalina host under VirtualBox 6.1.10.
It runs without problems, but, I cannot mount the Guest Additions disk and not access the shared folder as a regular user within the VM.
I removed, rebooted the VM, and added it again and rebooted the VM but the error persitsts.

Unable to insert the virtual optical disk /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso into the machine VM-Centos.
Result Code: NS_ERROR_FAILURE (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}
Callee: IMachine {85632c68-b5bb-4316-a900-5eb28d3413df}

And the file does exist.

ls -al /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso
-rw-r--r--@ 1 root admin 60448768 Jun 4 19:22 /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso
Screenshot 2020-07-10 at 13.28.07.png
Screenshot 2020-07-10 at 13.28.07.png (27.81 KiB) Viewed 2858 times
Another issue is that inside the VM, a regular user cannot access the shared folder, maybe it has to do with the guest additions issue which I cannot intsall.
Within the VM (as root):
ls -al /media
total 0
drwxr-xr-x. 3 root root 26 Jul 10 12:48 .
dr-xr-xr-x. 17 root root 237 Jun 11 10:34 ..
drwxrwx---. 1 root vboxsf 1344 Jul 10 13:28 sf_Downloads

I have added the user to the group vboxsf and when I login as user in the VM, it issues 'Permission denied' when I try to access a file for read in sd_Downloads.
But when I login as root within the VM I can access the shared folder.

The sf_Downloads folder is the shared folder om macOS /Users/user/Downloads.
macandroid
Posts: 27
Joined: 10. Nov 2018, 14:04

Re: Cannot mount Guest additions disk image

Post by macandroid »

Does really nobody know ?

I stumbled upon the same issue with another new (Ubuntu) VM, using the same host folder as the other one where it does work.

When I call 'mount' on the guest I see the line showing the line containing the shared folder :

On the guest 1 (where user 'klaas' can access the shared folder)

Code: Select all

klaas on /media/sf_klaas type vboxsf (rw,nodev,relatime,ttl=0,iocharset=utf8,uid=0,gid=125,dmode=0770,fmode=0770)
while on the guest 2 (where user 'klaas' can NOT access the shared folder)

Code: Select all

klaas on /media/sf_klaas type vboxsf (rw,nodev,relatime,iocharset=utf8,uid=0,gid=998,dmode=0770,fmode=0770,tag=VBoxAutomounter)
The only difference is 'tag=VBoxAutomounter' which I cannot control of.

Both VBox files contain the same line :

Code: Select all

      <SharedFolders>
        <SharedFolder name="klaas" hostPath="/Users/klaas" writable="true" autoMount="true"/>
      </SharedFolders>
On both guests I have done:

Code: Select all

sudo usermod -a -G vboxsf klaas
So this is completely weird.
scottgus1
Site Moderator
Posts: 20965
Joined: 30. Dec 2009, 20:14
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Windows, Linux

Re: Cannot mount Guest additions disk image

Post by scottgus1 »

It appears this one got missed.

The shared folders set by Virtualbox require that the Guest Additions be installed in the guest OS. So you won't be able to use Virtualbox-arranged shared folders until you are able to get the Guest Additions installed.

Web-searching:
Unable to insert the virtual optical disk NS_ERROR_FAILURE site:forums.virtualbox.org
reveals two things.
1. there might be a line missing from your posted error message. Did it also say:
Could not mount the media/drive '/Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso' (VERR_PDM_MEDIA_LOCKED).
If so, that's a common error with Linux guests.

2. Ejecting the presently-loaded CD or ISO from inside the guest OS, or completely shutting down not save-stating the guest then ejecting the CD/ISO from the guest's CD drive in the guest's Storage settings should fix the seize-up and allow the GAs ISO to be inserted. You would then run the installer from the guest's CD drive inside the guest OS.
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