In March, I wrote about a bug in SQL Server that could cause you to lose Performance Monitor counters, as well as other important sources of SQL Server performance data, if SQL Server was stopped and started while certain tools (such as Performance Monitor) were accessing the metrics ("Performance Metrics in SQL Server Stop Working When You Stop SQL Server," InstantDoc ID 45157). In response to that article, I received the following tip from a reader, who points out another gotcha:

"I'm running Microsoft Operations Manager 2005 (MOM) on all my servers. MOM uses the same sql counters that Performance Monitor uses to gather information about your servers. My counters disappeared all the time on multiple servers, and it took me a long time to figure out that it was the MOM service causing me the grief. The workaround is to stop the MOM service on any server I need to stop SQL Server on."

SQL Server 2000 Service Pack 4 (SP4) will fix this bug—another reason to apply the service pack.