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Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 19:15
by Jean Jacques Linux
Hi.

Host: WinXP SP3;

Guest: Debian 5.0;

Problem: Can’t mount shared folder. Mount command return protocol error.

What I did:

1. Successfully installed guest additions on Debian;
2. Made shared folder on host system (called “shared_folder”. D:\Virtual Box\shared_folder);
3. Made shared folder on guest system (called “shared_folder” too. /home/<user_name>/shared_folder);
4. Devices ? Shared Folders… ? I added a path to shared folder on my host system and set a folder name to “shared_folder”;
5. In bash I typed: #mount -t vboxsf shared_folder /home/<user_name>/shared_folder;
6. And recieved an error: /sbin/mount.vboxsf: mounting failed with the error: Protocol error.

Questions:

1. Does this feature works?
2. What I do wrong?
3. What is the reason of Protocol error?
4. How can I fix it?

Tnx.

Jean Jacques Linux

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 19:28
by Perryg
Jean Jacques Linux wrote:Hi.

Host: WinXP SP3;

Guest: Debian 5.0;

Problem: Can’t mount shared folder. Mount command return protocol error.

What I did:

1. Successfully installed guest additions on Debian;
2. Made shared folder on host system (called “shared_folder”);
3. Devices ? Shared Folders… ? I added a permanent folder called “shared_folder”;
4. In bash I typed: #mount -t vboxsf shared_folder /home/<user_name>/shared_folder;
5. And recieved an error: /sbin/mount.vboxsf: mounting failed with the error: Protocol error.

Questions:

1. Does this feature works?
2. What I do wrong?
3. What is the reason of Protocol error?
4. How can I fix it?

Tnx.

Jean Jacques Linux


Did you create the folder "shared_folder" under your home directory?
If not it can not find it. Thus the protocol error.

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 20:27
by Jean Jacques Linux
Yes, I made it. This is not the cause of protocol error. If you doesn’t set a shared folder on guest system, you receive a “no such file or directory” error, not a protocol error.

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 20:32
by Perryg
Jean Jacques Linux wrote:Yes, I made it. This is not the cause of protocol error.


Then the other thing that I would suggest is to change the name and remount the share.
Try something simple and without special charactors. This sometimes causes this as well as Caps.
Try something like "share" .

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 20:52
by Jean Jacques Linux
I tried it.

1. Made host shared folder: C:\shared;
2. Made guest shared folder: /home/<user_name>/shared;
3. Add shared folder C:\shared, folder name: shared;
4. #mount -t vboxsf shared /home/<user_name>/shared;
5. Protocol error.

Doesn’t work.

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 21:17
by Perryg
Jean Jacques Linux wrote:I tried it.

1. Made host shared folder: C:\shared;
2. Made guest shared folder: /home/<user_name>/shared;
3. Add shared folder C:\shared, folder name: shared;
4. #mount -t vboxsf shared /home/<user_name>/shared;
5. Protocol error.

Doesn’t work.


From what I see it should work. Permissions may need to be checked on the linux shared folder.

You might try just to see that it is not a selinux thing, is to create the shared folder as root in the /mnt directory.
Then see if you can mount to that one. If so then it may be strickly permissions.

These are the only thing that I have seen to cause the protocol error in Linux with VBox.

Re: Can’t mount shared folder. Protocol error

PostPosted: 16. Mar 2009, 21:36
by Jean Jacques Linux
Works!

Again, what I did:

1. Made shared folder on host system, D:\Virtual Box\shared;
2. Ran VirtualBox;
3. Ran virtual machine;
4. Linux finished booting, I logged in;
5. I added shared folder D:\Virtual Box\shared, named it “shared”;
6. I made guest shared folder being logged as a user, called it “shared_folder”. /home/<user_name>/shared_folder;
7. $su;
8. Being logged as a root I mounted the shared folder: #mount -t vboxsf shared /home/<user_name>/shared_folder;
9. And all began to work.

May be the problem was host and guest folders had the same names?

Anyway thx for hints, Perryg.

Re: Can’t mount shared folder. Protocol error

PostPosted: 17. Mar 2009, 12:07
by destroyedlolo
I have the same problem and it happen randomly : try to reboot your PC and you WM to see if it's still working.

In my case, it's working once on 3 or 5 tries :evil:

Re: Can’t mount shared folder. Protocol error

PostPosted: 17. May 2009, 22:12
by leManu
Try to mount using the following command :

Code: Select all   Expand viewCollapse view
$ sudo mount.vboxsf share mount_point


It works right for me (I'm running Ubuntu Linux 9.04 as guest under Vista)

Re: Can’t mount shared folder. Protocol error

PostPosted: 17. May 2009, 22:17
by baf
This is a problem with mount if the share is named the same as a folder where you are standing then you get that error.
Rename the share to something different.

Re: Can’t mount shared folder. Protocol error

PostPosted: 17. May 2009, 22:33
by Sasquatch
This issue is handled in my Shared Folders howto in the Linux Guests forum. viewtopic.php?f=3&t=15868

Closed. People should have read the VirtualBox FAQ, where the howto is linked to.