virtualbox.org

Using version Virtualbox 5.0.2 with Ubuntu 15.04 host.

Upgraded existing Windows 10 Pro guest to preview build 10525. A mapped shared folder to my home directory was previously mapped to the "E" drive on the guest OS. After installing windows build 10525, the drive is no longer present. Reinstalling guest additions did nothing. Removing and recreating the share did nothing.

I could still visit the share on the host with a UNC path (\\server\share\). Manually mapping the share and assigning it a drive letter works as expected.

Labelling a network share with a drive letter is purely a Windows guest OS software feature. Nothing to do with VirtualBox AFAIK. Consider the fact that Linux guests do not use drive letters at all.

Yes, but previously, when you setup a shared folder for the guest, Virtualbox extensions automatically assigned it a drive letter when starting the guest. This is no longer happening.

DFarmerTX wrote:Yes, but previously, when you setup a shared folder for the guest, Virtualbox extensions automatically assigned it a drive letter

No, it never did.

As I said, the labels applied to things is purely a matter for the guest OS.

DFarmerTX wrote:A mapped shared folder to my home directory was previously mapped to the "E" drive on the guest OS.

If this share was set up via the Virtualbox Guest Additions method as shown in the User manual, section 4.3, double-check that everything is still set up according to the manual. The manual does say:

With Windows guests, any auto-mounted shared folder will receive its own drive letter (e.g. E:) depending on the free drive letters remaining in the guest.

If you set up the shared folder by the usual Windows methods, without relying on any Virtualbox Guest Additions stuff, then the mount letter has to be set in the guest OS.

So whether the drive letter is automatically set depends on which way you set up the shared folder, via Guest Additions or the regular network way.

Note that Windows 10 is a beast-in-progress so things might break here and there for a while.

And I did test an auto-mount Guest Additions shared folder in an XP guest on Virtualbox 4.2.16, and it did automatically get a drive letter... A log-off is required to get the auto-drive-letter mount to show if the shared folder is set while the guest is running.

Something is probably just broken. Either wait a little for the dust to settle on Windows 10 and VB 5 or report to the developers on the Bugtracker.

FWIW, I updated the Windows 10 insider previews to Build 10525 on both an OSX and Ubuntu 15.04 host. When there was a previously installed shared folder I had to remove it, restart the guest, reinstall the GAs, restart the guest, Added a shared folder from the Devices menu, restart the guest. There will be in the Quick Aceess area of File Explorer, if you had previously accessed the folder an E: drive. At least for both of mine. That link will no longer be valid and you can right click on it and delete it. If you click on Network in File Explorer you should see VBOXSVR.