[Fixed] Shared Folder missing in Windows 10 guest -> fixed in 127166

[frg]

Starting with the latest Betas one of my shared folders is no longer available.

I am seeing errors in the log:
00:02:48.374481 VMMDev: Guest Log: 16:15:26.930810 automount Error: vbsvcAutomounterMountIt: RTStrToUtf16Ex failed on 'VMTransfer': VERR_BUFFER_OVERFLOW

I have 3 folders there. The readonly ones are fine. Just the one named vmtransfer with full access is missing. Also drives are mapped differently. They are now mapped using the last available drive letters. The different mapping is just an observation and ok for me. The problem started with it.

[frg]

Not fixed in Beta 3. I am using the latest 5.23 guest additions as a workaround.

[mpack]

I see that one of your shares used mixed capitalization: "VMTransfer". I have had that cause problems in the past. I would try "VMTRANSFER" or "Vmtransfer" (the latter is a capitalized name, not mixed case text).

Also, why in heavens name is your Win10 VM using an ancient VirtualBox v3.x layout (i.e. separate machines and harddisks folders)? VirtualBox v3 predates Win10 by something like 8 years!

You should remember to eject the GAs CD after installing the GAs.

[frg]

> I see that one of your shares used mixed capitalization: "VMTransfer". I have had that cause problems in the past. I would try "VMTRANSFER" or "Vmtransfer" (the latter is a capitalized name, not mixed case text).

I didn't rename the actual dir but already tried using an all small caps share name. Also tried to use a fixed mount point. No go. Imho clearly a guest additions issue.

> Also, why in heavens name is your Win10 VM using an ancient VirtualBox v3.x layout (i.e. separate machines and harddisks folders)?

Because it suits me. Having all machine images in one dir and all data disks on a separate drive. Makes manually backing them up to another PC easier and I have a better overview of the sizes and changed disks images. I occasionally mount them in other machines too.

> You should remember to eject the GAs CD after installing the GAs.

I usually do but sometimes just forget it

FRG

[socratis]

Host OSX 10.11.6, VirtualBox 6.0.0b3, guest Win10-64, 1607, 14393 (a rather old).

Imho clearly a guest additions issue.

I've never had issues with my shares being CamelCase. I have actually two shares for all my VMs:

• "/Users/Shared/VirtualBox/ReadWrite" shared as "ReadWrite" and
• "/Users/Shared/VirtualBox/ReadOnly" shared as "ReadOnly"

The same shares are of course for my Win10 guest, which I tested and passed with flying colors. I didn't have them to auto-mount, so I changed that, and that still worked, no problems.

@frg
Can you remove the share, start the VM, make sure that everything is working, shut down the VM and re-create the share?

I don't particularly like that RTStrToUtf16Ex mention in there. Why would it fail? You're not using non-ASCII characters in there by any chance, are you?

[socratis]

Well that is one funny error. Tried it in a Vista x64 too. Any shared folder name with 10 or more chars fails. Maybe someone else can try this too. This is a 8.1 host. Will boot 7 later and check it there.

00:00:04.595711     Host path 'H:\Soft\Microsoft', map name 'Microsoft', read-only, automount=true, automntpnt=, create_symlinks=false, missing=false
00:00:04.595869 SharedFolders host service: Adding host mapping
00:00:04.595880     Host path 'E:\Software', map name 'Software', read-only, automount=true, automntpnt=, create_symlinks=false, missing=false
00:00:04.596007 SharedFolders host service: Adding host mapping
00:00:04.596013     Host path 'F:\Z1234567', map name 'Z1234567', writable, automount=true, automntpnt=, create_symlinks=false, missing=false
00:00:04.596125 SharedFolders host service: Adding host mapping
00:00:04.596131     Host path 'F:\Z12345678', map name 'Z12345678', writable, automount=true, automntpnt=, create_symlinks=false, missing=false
00:00:04.596241 SharedFolders host service: Adding host mapping
00:00:04.596247     Host path 'F:\Z123456789', map name 'Z123456789', writable, automount=true, automntpnt=, create_symlinks=false, missing=false
00:00:04.596353 SharedFolders host service: Adding host mapping
00:00:04.596359     Host path 'F:\Z1234567890', map name 'Z1234567890', writable, automount=true, automntpnt=, create_symlinks=false, missing=false

00:00:41.484710 VMMDev: Guest Log: 12:31:58.717326 automount vbsvcAutomounterMountIt: Successfully mounted 'Microsoft' on 'Z:'
00:00:41.489231 VMMDev: Guest Log: 12:31:58.717326 automount vbsvcAutomounterMountIt: Successfully mounted 'Software' on 'Y:'
00:00:41.493598 VMMDev: Guest Log: 12:31:58.717326 automount vbsvcAutomounterMountIt: Successfully mounted 'Z1234567' on 'X:'
00:00:41.498452 VMMDev: Guest Log: 12:31:58.734486 automount vbsvcAutomounterMountIt: Successfully mounted 'Z12345678' on 'W:'
00:00:41.505734 VMMDev: Guest Log: 12:31:58.734486 automount Error: vbsvcAutomounterMountIt: RTStrToUtf16Ex failed on 'Z123456789': VERR_BUFFER_OVERFLOW
00:00:41.510575 VMMDev: Guest Log: 12:31:58.734486 automount Error: vbsvcAutomounterMountIt: RTStrToUtf16Ex failed on 'Z1234567890': VERR_BUFFER_OVERFLOW
00:00:42.520814 VMMDev: Guest Log: 12:31:59.849893 automount Error: vbsvcAutomounterMountIt: RTStrToUtf16Ex failed on 'Z123456789': VERR_BUFFER_OVERFLOW
00:00:42.537637 VMMDev: Guest Log: 12:31:59.867053 automount Error: vbsvcAutomounterMountIt: RTStrToUtf16Ex failed on 'Z1234567890': VERR_BUFFER_OVERFLOW

[bird]

Thanks for the report. Buggy output buffer calculation for a string conversion. Will be fixed in the next build.
- bird

[socratis]

Just for completion, I just verified the issue and I tested it with both RW and RO shared folders. The RO/RW doesn't matter, it's the length of the share name that matters.

[frg]

Fixed in guest addtion 127166. That was done fast

Thanks
FRG

[socratis]

That's what a well laid out case with a reproducible scenario will do.
Thanks for marking it as fixed.