Answers to your questions:

After the upgrade to the 2.0.5 tools the Windows VM was rebooted, is that correct? --> YES

Then accessing your Z: drive gives you the error message, can you upload a screen shot of the error message? --> see it attached (I'm sorry, it's in Spanish, but fully understandable, I hope)

Also using a command prompt and issuing:
net use z: /D
net use z: file://.host/Shared Folders
cd /d z:\
This also results in an error too? --> same error

How about if you replace the z: above with a different drive letter? --> I did try it before, same problem

Can you access any drive letter mappings to VMware shared folders? --> no by mapping, I can access navigating from the desktop shortcut or from "My networks"

Furthermore, what does the registry setting key have (using regedt32.exe)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\vmhgfs\networkprovider\
Key: ProviderPath
Type: REG_SZ
Value: "C:\Windows\System32\vmhgfs1.dll"
Or
"C:\Windows\System32\vmhgfs.dll"
--> it says "C:\Windows\System32\vmhgfs1.dll"

If you use Explorer and right click on properties and version tab for this file, what does the "File Version:" say? --> 8.0.6001.18702

Hope it helps,

David Esteban

NEW - NEW - NEW

I've uninstalled VMware Tools, completely, and installed them again from scratch. It works now. I've got unit Z: back, working perfectly well.

I'm somewhat surprised, however, seeing that I've an A: unit (????) and a D: unit VMware Tools. (????) --> see file attached

David Esteban

No floppy disk, I'm afraid (MacBook Pro machine) ... as far as the D: unit I understand it has been mounted by the installation process ... is that correct? (I can not see it on the Mac's desktop ...