How do I get full access to a network computer hard drive using UNC path network browsing?

Yes. I have been working on that computer via RDP.

From http://support.microsoft.com/kb/304040/ :

When Simple File Sharing is turned on, remote administration and remote registry editing does not work as expected from a remote computer, and connections to administrative shares (such as C$) do not work because all remote users authenticate as Guest. Guest accounts do not have administrative rights. When Simple File Sharing is turned on, if you configure specific user ACEs, remote users are not affected when Simple File Sharing is turned on because all remote users authenticate as Guest when Simple File Sharing is turned on.

so, switch Simple File Sharing off and assign permissions the old fashioned way... but why is it working on the other PC's?

I don't know.  The only reason I remembered this is because I wanted to setup a remote logon to one of my XP computers and I had to go thru this (and create a new user) to be able to logon.  Even then it was only to the particular directory where I had changed permissions and added the new user.

I would go to one of the 'other' computers and see if maybe someone already went thru the procedure to allow logon access.  On the other hand, if simple file sharing is turned on, you should (?) be able to access the drive by name like \\computer\c12 or whatever without a logon.  That's the way it works here except that I'm in a workgroup, not a domain.

Are you a domain admin?

You cannot connect to a C$ share unless you are an admin/domain admin account.

Only reason I ask is that you say "I can connect to it via Remote Desktop with a  domain admin account. Domain Admins have Full Control on the default C$ share"  which makes me believe you are not using a domain admin account to access it.

Yes. I am a domain admin, and I am connecting via a domain admin account and password.

Normally if I try to connect to a share via UNC with a non admin account a window will pop up requesting a username and password. In this instance I never see that window. I just get the error message that the "network path was not found".

I am able to browse to other computers on the network from the problem computer. I definitely have network connectivity. I'm guessing there must be some network share permission, or some protocol configuration I've missed?

Hi

Leave the Simple File Sharing switched off.

Open Control Panel > Administrative Tools > Local Security Policy > Security Settings

Change the 'Local Policies > Security Options > Network Access: Sharing and Security Model For Local Accounts' option from 'Guest Only' to 'Classic - local users authenticate as themselves'

Hopefully this works.  I have had to use this on countless occasions, especially for deploying Sophos in a peer to peer windows network.  If it does work, then you could obviously deploy this to your network using a Group Policy.

Let me know how you get on.

That was a good suggestion. I had not thought of looking at the local security policies. Unfortunately it did not address the problem. I am still having UNC path and browsing problems when I try to access that computer. RDP works fine and of course I can ping that computer from any other computer on my domain. Although the computer shows up when I browse to Microsoft Windows Network > Domain if I try to click on it I get the following error message: \\computername is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. The network path was not found.

Run > \\UNCpath\C$  simply returns the error message: The network path was not found.

I looked at the Local Disk security permissions and found that the Everyone account was missing. I added the Everyone account (this is temporary - I realize this is not a best practice) and allowed the following special permissions on the C: folder only: Traverse Folder /Execute File, List Folder/Read Data, Read Attributes, Read Extended Attributes, Read Permissions.  But this did not fix the problem either.  

What am I missing? Any other ideas?  Thanks!
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Our domain controller synchronizes with a world time clock so I do not believe the issue is caused by a time difference. Interesting point about the domain account group membership, but I never get the opportunity in this case to provide a login because it cannot find the network path. Thanks for sending the link to KB article 887303.  It covers a few things I haven't looked at yet.  I will go through it in detail and report back if I have any success.

Here is one more piece to the puzzle that I forgot about. The hard drive on the problem computer (a laptop) has a clean install of Windows XP that was installed when the drive was connected to another motherboard. The old motherboard had no network connectivity at all and Windows XP was reinstalled at the time to troubleshoot that problem.  I confirmed that the hardware was bad and our motherboard was replaced by the manufacturer.  Our desktop support person decided to rebuild the PC using the Win XP OS that was already installed.  Could this different motherboard be a factor?  Could there be some registry setting somewhere that needs to be changed?  Does anyone have any thoughts on that?

I checked the system time on the problem PC. It has the same time as our domain controller. The PC and the domain controller are synchronized to the same source.

I ran C:\>net share to see if any of the administrative shares were missing on this system. Everything is there. None of the shares are missing. Here's the output:
Share name   Resource                        Remark
-------------------------------------------------------------------------------
ADMIN$       C:\WINDOWS                      Remote Admin
C$           C:\                             Default share
IPC$                                         Remote IPC

I looked at HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters\ and HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Lanmanworkstation\Parameters\ to see if either the AutoShareServer key or the AutoShareWks key had a value of 0. Neither DWORD value was present. "If these values do not exist, you do not have to create them because the default behavior is to automatically create the administrative shares."

I figured out the problem when I disabled Symantec Endpoint Protection v. 11.0.4014. I was able to browse via UNC path with SEP disabled. I re-enabled it and tried to browse from my PC again via UNC path. The following SEP message was displayed on the PC I could not connect to: "Traffic has been blocked from this application: (ntoskrnl.exe)."  It is the Network Threat Protection portion of the program that is blocking browsing across the network.

The problem computer (laptop) has an unmanaged SEP installation that has to be individually configured. The other computers on our network have not had this problem because they all have centrally managed SEP installations. Now all I need to do is figure out how to allow traffic to get through with SEP Network Threat Protection enabled.  

I created a new firewall rule in SEP that allows network traffic from the IP addresses within our network that require the ability to browse via UNC path for the purpose of either troubleshooting or running a backup.  The problem is solved. Thanks for your assistance!

Hmm...  With you saying in your original post that Windows Firewall was switched off, I (and I think everyone else did as nobody mentioned firewall) presumed no firewall was installed on the PC with it being internal on the network.

It would have saved you, me and the rest of the contributors a lot of time if you had!

Well, I suppose it's a lesson learned - don't overlook the obvious!

Glad it's sorted.

Glad to hear that you found the cause and solved the problem.  I may be having the same problem with the Norton version of the Symantec product.  Something is blocking access to new files on a computer that is running a different antivirus.