The NAS should be configured to allow access to all accounts. We will not know the password the media centers are using so we need them to be allowed to connect without supplying a password.
First find out what media extender accounts will be needing access to the NAS. To do this, on the Media Center PC (Vista), go to Control Panel>System>Advanced System Settings>Advanced Tab>Under 'User Profiles' click the Settings button. Write down each Mcx account. Example, Mcx1, Mcx2, Mcx3. The example indicates three extenders have been added to the Media Center.
The directory you will be saving this to probably will not exist yet so create it. To create, go to Start>Computer>click the drive letter Vista is installed on. By default this will be C:. Click Windows, click System32. In the right pane, right click in the white space and choose 'New>Folder'. Name the folder Repl. Now click Repl. Right click again, New>Folder and name it Import. Click Import, right click, New>Folder and name is Scripts.
Next, create the drive mapping script. To do this open Notepad (Start>All Programs>Accessories>Notepad
The drive letter to use in the script should be the same as what you use when you work on the NAS from your Media Center. If you make a mapping called 'z:' then use 'z:' in the script. The script should look like this.
net use z: /delete /y
net use z: "\\your_NAS_server\the_folder_to_map_to" /persistent:no
Quotes are not required around the path unless the path has spaces in it, then you do have to use the quotes. Safe bet is just to quote it. If you have additional drive you want mapped just type the same thing on the next line for each one. The first line is to delete any existing mapping, the second line establishes the mapping. The first line is not required but, like the quotes, it is a good practice and will not hurt.
In Notepad go to File>Save As>change 'save as type' to all files. Name the file whatever you want (ie: mcx1_mapping.cmd). When you save it make sure you type the .cmd (the extension). You will need this script name later so write it down if you easily forget. Save the file to the folder we created above. If Vista is on C: you will save it to C:\Windows\System32\Repl\Import\Scripts
Now go to Start>All Programs>Accessories>right click on Command Prompt and choose 'Run as Administrator'. If you have the UAC disabled, you don't have to choose to run it as administrator. At the command prompt type:
net user mcx1 /scriptpath:mcx1_mapping.cmd
and hit Enter. If you are doing this for another account, say Mcx2, then it would be net user mcx2 rather than mcx1. Also, obviously, the script name you specify should match the name you used.
Now test this with the media center extender. If you have media cente open on the extender close it. Open media center on the extender. Now if you have movies on your NAS that were added to MyMovies, you should be able to watch them rather than getting the 'path not found' error.
I don't have a NAS. I was instructed on this by another (Andy K.). Thanks Andy. I would appreciate any trial and error feedback on this so I can make sure these instructions are correct. If you get a chance to test this I would appreciate your comments. Email me or leave comments on here. By the way, I don't run the UAC on my Vista machine. It seems more of a problem than it is worth. Andy confirmed he does run it and this method worked for him.
Here is a sample you can use to help...Download this zip file. Extract it somewhere, like your desktop. Open the folder. Right click the mcx.mapping cmd file. Choose Edit. Alter the text to match the mcx account you want, the path to your NAS share, and the drive letter. After making your changes, go to File>Save. Now right click the setup.cmd file and choose edit. On the net user line, alter the mcx account to match the one you are mapping for. Also, if Vista is not installed on C:, change the letter on the first line. Now go to File>Save. Right click the setup file again and choose 'Run as Administrator'. This will make the folders, copy the mcx_mapping.cmd to the folder, and then set the net user logon script.
More information:
http://thegreenbutton.com/forums/thread/260952.aspx
http://blogs.msdn.com/mpoulson/archive/2005/01/17/354999.aspx
http://thegreenbutton.com/forums/2/206983/ShowThread.aspx
http://technet.microsoft.com/en-us/library/bb490718.aspx