Limit of Two Concurrent Print Queues from Windows NT to LANMan

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1
• Microsoft LAN Manager version 2.2

SYMPTOMS

When a computer running Windows NT version 3.1 is configured to redirect several print queues from a LAN Manager for UNIX 2.2 server, the system reports the following in the event log:

   System Error 1220
   AN ATTEMPT WAS MADE TO ESTABLISH A SESSION TO A LANMANAGER SESSION BUT
   THERE ARE TOO MANY SESSIONS ALREADY ESTABLISHED.

CAUSE

This error occurs because of a Windows NT redirector limit of two sessions with an OS/2 server.

Some OS/2 and LAN Manager for UNIX servers can only handle two login sessions from one client. The Windows NT version 3.1 redirector can't tell whether the OS/2 server is one that supports only two logons, or if it supports more, so it tries two (even though Microsoft LAN Manager version 2.2 supports more than two).

RESOLUTION

WARNING: Using 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 Registry Editor can be solved. Use this tool at your own risk.

To resolve this issue:

1. Upgrade to Windows NT version 3.5.

2. Run Registry Editor (REGEDT32.EXE).

3. From the HKEY_LOCAL_MACHINE subtree, go to the following key:

         \SYSTEM\CurrentControlSet\Services\Rdr\Parameters
   

4. From the Edit menu choose Add Value.

5. Add the following:

         Value Name: Os2SessionLimit
         Data Type:  REG_DWORD
         Data:       100
         Radix:      Hex
   
   

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.1. This problem was corrected in Windows NT 3.5. This problem was corrected in the latest U.S. Service Pack for Windows NT 3.1. For information on obtaining this update, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K