Troubleshooting file-sharing problems

You have to be at the meeting in a few minutes, but you can't access that all-important document you're supposed to be able to access. This article explores several techniques you can use to diagnose and correct file-sharing problems.

At one time or another, most of us have been frustrated by not being able to access a file or other resource we’re supposed to be able to access. Not only is such a situation frustrating, it can really cut into your productivity. Every minute you spend fighting with the computer is a minute you could have spent working on your project. In this Daily Drill Down, we'll explain some techniques you can use to diagnose and correct problems with file sharing.
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Where is the file?
Before you can begin the diagnostic process, you first must ask yourself the simple question, "Where is the file located?" Although it may seem like a no-brainer, it's a critical step. Before you even think about troubleshooting, you need to know the name of the machine that contains the shared resource, the name of the share point associated with the resource, and, most importantly, whether the file resides on a Windows NT machine or on a Windows 98 machine.

Basic techniques
The technique you use for troubleshooting will depend heavily on which operating systems are involved. However, before we get into the nitty-gritty of OS-specific techniques, you should check some things that apply to both operating systems. I suggest that you perform the following tests in the order that I discuss them.

Test connectivity
One of the first steps in the troubleshooting process is to test the connectivity between the computer containing the shared resources and the computer that's trying to access the shared resources. The easiest way of doing so is to try to access another share on the same computer. If you can access the share, the connectivity is good. If you can't, you need to figure out why.

Start by checking out which network resources both machines can access. If one computer can access most of the network but the other computer can't access anything on the network, there's obviously a problem with the second computer's configuration. If that's the case, you need to begin the basic network troubleshooting techniques, such as checking for a bad cable or network card and reloading the network client.

If both PCs can access part of the network but can't see each other, you may have a routing problem. This problem can occur when the two computers reside in different subnets and the router is set up incorrectly. Such a problem can also occur if there's a protocol mismatch. For example, if the PC with the shared resource is running TCP/IP but the computer that's trying to access that resource has only NetBEUI loaded, the two PCs won't be able to communicate because they share no common protocols. You can easily correct the problem by adding the necessary protocol to the computer that's trying to access the shared resource.

Try accessing other shares
If you were able to access another share on the computer, or if the computer that’s hosting the shared resource is available through Network Neighborhood, there's most likely either a permissions problem or a problem with the way you're trying to access the resource.

You can eliminate the latter possibility by launching IE and entering the UNC path to the share in the Address bar. If using the UNC reference gets you into the shared resource, you're in business. You can map a network drive letter to the resource to make accessing it easier. But if you still can't access the shared resource, it's most likely a permissions problem.

One way of checking is to log in as a user who isn't having trouble with accessing the share and to try to access the resource. If you can access the resource as that user, it's definitely a permissions problem. If no one can access the share from any PC, it still may be a permissions problem. As I mentioned earlier, the method you'll use to troubleshoot a permissions problem will depend on the operating system that the PC hosting the file is running. We'll begin by discussing what to do if that PC is running Windows NT; we'll discuss Windows 98 later in the Drill Down.

Windows NT Server
As you probably know, security is Windows NT's specialty. Therefore, it's entirely possible that Windows NT has been set accidentally to deny access to the resources in question. In the sections that follow, we'll discuss some techniques you can use to track down these accidental denials of resources.

File permissions vs. share permissions
It's important to point out that Windows NT is capable of setting permissions at the file level and at the share level. When you’re fighting a permissions problem, keep this fact in mind. Having full access to the share won't do users any good if they've been denied access at the file level.

Checking a share's permissions
To check the file-level permissions, right-click on the directory that contains the resources and choose the Properties command from the shortcut menu. When the folder's properties sheet appears, select the Security tab and click the Permissions button. You’ll see the permissions that are assigned to the directory, as shown in Figure A. Usually, the same permissions will apply to all the files and directories beneath that point, but if you want to make sure, select both check boxes that are shown in the figure and click OK.

Figure A
Make sure that the appropriate permissions are set at the file level.

Next, you need to check the share’s permissions. Just right-click on the directory in question (or a shared directory above it) and select the Properties command from the shortcut menu. When the directory’s properties sheet opens, select the Sharing tab to display the share information shown in Figure B. Verify that the directory is being shared and confirm the share name and the number of users who are allowed to access the share.

Figure B
Verify the share name and the number of users who are allowed to use the share.

Finally, verify the share’s permissions by clicking the Permissions button. When you do, you can verify access to the share, as shown in Figure C.

Figure C
Make sure that the necessary permissions are applied to the share.

Who owns the file?
If you've checked the file and share permissions but are still having no luck, try checking the resources ownership. In some situations, Windows NT has been known to deny access to everyone except the owner of a folder. To check for this condition, right click on the folder and select the Properties command from the shortcut menu. When you see the folder’s properties sheet, select the Security tab and click the Ownership button. Doing so will display the folder’s ownership information, as shown in Figure D. If you want to make a change, click the Take Ownership button.

Figure D
Use the Owner dialog box to verify ownership and to take ownership, if necessary.

Windows 98
Windows 98 is much easier to check than Windows NT because it deals only with share permissions, not with file permissions. Therefore, as long as users have appropriate rights to the share point, nothing is stopping them from accessing the resource. You can set security on a share by using one of two methods, which we’ll discuss next.

Share-level access vs. user-level access
To see which security model Windows 98 is set to use, open Control Panel and double-click the Network icon. When the Network Properties sheet appears, select the Access Control tab. As you can see in Figure E, the type of access can be set to either share-level access or user-level access.

Figure E
Windows 98 can be set for share-level access or user-level access.

Share-level access allows you to protect each share point with a password. You can use one password for read-only access and another password for full access. User-level access allows you to specify which users have what type of access to any given share.

If the system is set to use share-level access but you're still having trouble accessing it, you might try temporarily removing any passwords you've assigned to the share and seeing if that makes a difference. If you find the passwords to be the cause of the problem, check the case you're using to enter the passwords—Windows passwords are case-sensitive.

If you choose user-level access, verify that your name is on the list. If it is on the list but the permissions are set to read-only, try setting full permissions. If that doesn't work, try accessing the share as one of the other users on the list.

If nothing works, try removing the share. Once you've done so, reboot the computer and reestablish the share.

Although I've tried to guide you through the process of troubleshooting most of the more common file-sharing problems, it's impossible to cover every possible situation. For example, there are some strange file-sharing problems associated with Windows 98 computers that are attached to some types of NetWare servers. However, space prohibits me from even beginning to talk about NetWare. If you run into a strange file-sharing problem that I wasn’t able to cover, I suggest that you search the Microsoft Knowledge Base .

Talainia Posey learned to handle PCs the old-fashioned way: by reading manuals and doing on-the-job troubleshooting. Her experience also includes installing networks for several small companies. When she's not working on computers, Talainia loves to shop for toys, watch cartoons, and spend time with her cat, Beavis.

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