Cannot mount removable disk if not already attached while guest boot

[akota]

Hello

I experience a problem with a Windows host & Linux guest on Virtual Box 6: While I can perfectly mount and umount shared disks as soon as they are already mounted in the host system when the guest starts, nevertheless, I cannot do it if they are not but are rather attached later.

More specifically, if I have an external disk already mounted in the host system and I start the VM, I can then mount it, umount it, plug it off completely, then replug it and mount it back. No issues with that; all works perfectly. On the other hand, if when I start the VM the disk is not already attached, then no matter what I do, I get the message:

/sbin/mount.vboxsf: mounting failed with the error: Protocol error

I have the guest additions and extension pack in sync. I have been using VB for years; I want to believe I didn't make some newbie mistake.
I remember I didn't have this problem on a Linux host, but I cannot tell whether the problem is the host OS or a newer VB version.

Any idea?

[socratis]

with a Windows host & Linux guest on Virtual Box 6

Windows what? Windows for Workgroups 3.11? Win2K? Win10 insider?
Same with the "Linux guest" and VirtualBox; there can be a lot of Linux guests, and there's no VirtualBox version 6. It's either 6.0.0, .2, .4, .6, .8 or .10 that was released a couple of days ago.

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

[akota]

Thanx for your reply. I thought that the OS I use was visible in my account details next to the post. Anyway, here are the details:

• Host OS: Windows 10
  Guest OS: Kubuntu 16.04
  VBox version: 6.0.10

I uploaded two VBox log files, one with a successful run and one with a failed one. The difference was that in the first, the external disk was already mounted during VM boot, while in the latter, the disk was not mounted.

In the first case, the relevant line in the log was this:

Code: Select all

Host path 'X:\', map name '_EXT_', writable, automount=false, automntpnt=/, create_symlinks=false, missing=false

in the latter case the error was this:

Code: Select all

Host path 'X:\', map name '_EXT_', writable, automount=false, automntpnt=/, create_symlinks=false, missing=true
ERROR [COM]: aRC=E_INVALIDARG (0x80070057) aIID={872da645-4a9b-1727-bee2-5585105b9eed} aComponent={ConsoleWrap} aText={Shared folder path 'X:\' does not exist on the host}, preserve=false aResultDetail=0

Let me stress here that the shared folder was NOT declared as "Auto-mount" in the settings. So I should expect that there be no error issued. Apparently VB is taking account of all the mounts including the non-auto-mounted ones at start, and the absence of the X: caused some internal "damage" that prevented me from later mounting the disk even though X: did appear.

But is this really the expected behavior? How else a newly mounted disk in windows (which will get a new - not yet existent - label letter) will ever be mounted at a later time in the VM?