JUST THIS MONTH, we have started getting reports from a number of very stable clients that MrxSmb event id 50 errors keep appearing in their system event logs. Otherwise, they do not appear to have any networking problems except that there is a critical legacy application which seems to either be generating the MrxSmb errors or having errors occur because of them. The legacy application is comprised of 16 bit and 32 bit code and has not been changed or recompiled in many years. It has always been stable on Windows XP systems. The customers that have the problem usually have a small (5 clients or less) peer to peer network with all Windows XP systems. All service packs are loaded on the XP machines.

Note: The only thing that seems to correct the problem is disabling opportunistic locking. I don't like this solution because it seems to slow down the network and sometimes causes record locking issues between users (on some networks). Also, this seems to have just started happening - as if a Windows update for XP has caused it? However, I have removed recent updates and it did not correct the issue.

Thanks in advance for any help you can provide.