I went back and spent most of the weekend trying to resolve my problem. I've also reviewed many related posts.
The user manual is very hard to understand. Acronyms are used in many places yet are seldom defined in the Glossary.
For example I started reading from Chapter 1 (page 9). On page 10 I was referred to page 18 (to check supported operating systems). Under Mac OS on page 19 I’m referred to page 224 for known limitations. That page is covered with acronyms, VDI files, VMDK and VHD formats, and OVF import/export, none of which mean anything to me. Only OVF (Open Virtualization Format) is defined in the glossary and that definition leads you into Chapter 3.8 before it is really explained.
Moving on to Chapter 3. Finally on page 35 there is a comment about VDI files that leads to Chapter 5.2 I where they define VDI (Virtual Disk Image) files as: VirtualBox uses its own container format for guests hard disks.
Back to Chapter 3.
Now the fun begins. Section 3.4.2 Changing removable media refers you to 3.3, Basics of virtual machine configuration page 36. 3.3 basics of virtual machine configuration refers you to 3.7 Virtual machine settings on page 45, which in turn directs you to Chapter 8, VBoxManage Reference on page 100. That is just is command line listing which does not help the new VirtualBox user at all.
If you are able to retrace your steps back to 3.7 Virtual Machine settings and move from page 46 to the top of page 47 you find useful data about the Virtual machine settings but I didn’t see that section the first several times I read the manual because the reference to Chapter 8,VirtualBoxManage reference at the bottom of page 45 got me lost. Would someone PLEASE move that reference to the end of the 3.7 section, i.e., just before section 3.8.
Finally found a reference to shared folders in section 3.7.10 but that just directs you to Chapter 4.6, Folder sharing.
(I have also checked section in Chapter 8, VBoxManage reference on Shared Folders (8.22 on page 122) but that just refers you to Chapter 4.6.)
Followed the instructions in 4.6 very carefully and made a conscious decision to use X:, Y: and Z: as the drive letters for my shared VirtualBox drives so that these drive letters in my notes to myself will clearly stand out. The first will be used for my Paint Shop folder located under my UserID, in a subfolder of Pictures named 2010-Calendar, the second for my Class Lecture Notes folder in Documents and the last for VBoxTemp folder in Documents that will contain everything else. Got the message “The command completed successfully.” after each in the DOS prompt window.
Didn’t make any difference. I still get the same error that I’ve had since last summer. When I click on the 2010-Calendar on ‘vboxsvr’ (X:) icon in the Network drives section of My Computer inside Windows I get a pop-up window labeled “My Computer” with the first sentence stating “X:\ refers to a location that is unavailable.”
Found one suggestion to not use special characters or capital letters. Opened an Explorer Window and deleted my network drives, went to the VirtualBox’s menu bar and selected Devices and Shared Folders where I changed the shared name to all lower case, then I opened a Command Window and re-created them with the new names. When I used Explorer to test them I got the same error as above. Closed the VirtualBox and restarted it still had the problem. Went back deleted the Windows drives, then deleted the VM Shared folders under Devices, closed the VM, changed the files names on my Mac to they didn’t use capital letters or special characters and verified that they when shared folders. Restarted my window’s VM and setup shared folders again from the Devices menu and then within Windows. The problem remains: I get a pop-up window labeled “My Computer” with the first sentence stating “X:\ refers to a location that is unavailable.” whenever I try to open a shared folder.
I’ve also tried capital letters and lower case letters for the drive letters and tried defining then shared folders inside windows with the undocumented –p option that was suggested in some posts. These made no difference; I still get the same error.
So I'm stuck at the same point I was last August. Any suggestions?