Windows special folders mount as read only when shared

[TrevorW]

Windows uses the 'read only' attribute for folders to indicate that the folder is a special folder such as 'Downloads', 'Documents, 'Pictures', 'Videos' and 'Music'. Consequently this attribute is not intended to indicate that the folder is actually read only or that files should not be able to be created within it (​https://support.microsoft.com/en-gb/kb/326549). Unfortunately Virtual Box does not respect this behavior when mounting a shared folder that contains such folders.

An example of this problem is that if the 'Downloads' special folder is moved to the root directory of drive 'D:' and then drive 'D:' is shared with an Ubuntu client, then it will be impossible to create files or folders within the 'Downloads' folder from within the Ubuntu client. Nor will it be possible to change the permissions from within the Ubuntu client.

There is a workaround (​https://forums.virtualbox.org/viewtopic.php?f=3&t=46541), which involves removing the read only attribute from within Windows using the command line 'attrib' command (Explorer does not permit the read only attribute to be removed from folders).

This is not an ideal solution as it removes some of the special folder behavior within Windows. Ideally, VirtualBox should respect the normal Windows behavior of the read only attribute and ignore it. This should be a very simple matter to fix.