Windows 95/98 Clients Hang with "Mprexe.exe Not Responding" Error Message

Windows 95 clients using Microsoft distributed file system (Dfs) or Windows 98 clients may stop responding (hang) in any of the following situations:

• Windows 95 Dfs clients or Windows 98 clients hang while logging on to a Windows NT 4.0 domain controller that has a Dfs root share and SQL 7.0 installed.
• After successfully logging on to a domain, Windows 95 Dfs clients and Windows 98 clients hang when trying to connect to or browse a Windows NT 4.0 domain controller (or member server) that has a Dfs root share and SQL 7.0 installed.
• Windows 95 Dfs clients or Windows 98 clients hang while logging on to a Windows NT 4.0 domain controller, if the user has a logon script that maps a drive to a Windows NT 4.0 domain controller (or member server) that has a Dfs root share and SQL 7.0 installed.

When a user is trying to log on, Windows 98-based computers may display Creating User Profiles and Loading System Policies dialog boxes, and then hang. If you press CTRL+ALT+DELETE, you see that Mprexe.exe is not responding.

NOTE: This problem has also been observed in environments without SQL or Dfs; the problem was resolved using the solution listed above. Mprexe.exe may not be responding for many underlying reasons. This article addresses one possible solution.

SQL 7.0 installs the following key on the SQL server, which Windows 98 clients and Windows 95 Dfs clients cannot process correctly: This key has a REG_DWORD value of x1FF.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

1. Start Registry Editor (Regedt32.exe) on the Windows NT 4.0 server that has the Dfs root share and SQL 7.0 installed.
2. Locate the REG_DWORD x1FF value under the following key in the registry:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer\Parameters\MaxMpxCt
3. On the Edit menu, click DWORD, type 1FE, click Hex, and then click OK.
4. Quit Registry Editor.
5. Reboot the computer.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

The problem does not affect Windows NT Workstation or Windows 95 clients that are not Dfs-aware.

If you click Cancel at the domain logon prompt, you can log on locally.

Other possible solutions include:

• Move the Dfs root share to a member server or domain controller that does not have SQL 7.0 installed.
• Install the NWLINK protocol on all servers and clients.
• If you stop the Netlogon service on the domain controller that is running Dfs and SQL 7.0, you should be able to log on to the domain (provided that there are other domain controllers that can be reached by the client) but unable to browse the domain controller running Dfs and SQL 7.0.
• Apply SQL Server 7.0 Service Pack 1 (SP1).