Access Violation Using MPR and Third-Party Network Provider

• Microsoft Windows NT Workstation versions 3.5 and 3.51
• Microsoft Windows NT Server versions 3.5 and 3.51

SYMPTOMS

An application that uses the Multi-Protocol Router (MPR) and a third-party network provider does not start and an Access Violation error message appears.

CAUSE

According to the Win32 documentation, a null character is required at the end of the network provider path in the registry. When MPR.DLL reads the path of the third-party network provider, a null character is not found.

WORKAROUND

To resolve this problem, upgrade to Windows NT Workstation and Server version 4.0.

To work around this problem, do the following:

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

1. Start Registry Editor (REGEDT32.EXE) and locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:

   \SYSTEM\CurrentControlSet\Control\NetworkProvider\Order

2. Select the ProviderOrder value name and note the name of the third-party provider.

3. Locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:

   \SYSTEM\CurrentControlSet\Services\<third-party provider>

         \networkprovider
   

4. Select the ProviderPath value name. From the Edit menu, select String.

5. Press CTRL+C to copy the string to the clipboard.

6. Remove the string and click OK.

7. Select the ProviderPath value name. From the Edit menu, select String.

8. Press CTRL+V to copy the contents of the clipboard to the string.

9. Click OK and quit Registry Editor.

10. Shut down and restart Windows NT.

STATUS

Microsoft has confirmed this to be a problem in Windows NT versions 3.5 and 3.51. This problem was corrected in Windows NT Workstation and Server version 4.0.