Hello all, I am having a problem with NSClient - maybe somebody else has experinced the same problem and can help ? I am trying to query performance counters on a 2000 Server. Here is my command definition..... define command{ command_name check_nt_perf_counter command_line $USER1$/check_nt -H $HOSTADDRESS$ -p 1248 -v COUNTER -l $ARG1$ -w $ARG2$ -c $ARG3$ } And here is my service definition.... define service{ service_description NT Paging File check_command check_nt_perf_counter!'"\\Paging File(_Total)\\%% Usage"'!50!80 use service_template max_check_attempts 3 check_period 24x7 normal_check_interval 5 retry_check_interval 5 notification_interval 360 notification_period WorkingHours notification_options w,c,r contact_groups it_department name nt_memuse_service register 1 host_name NTBOX } (NB I use a quote and then a double quote above in my def to push the quotes through) Nagios compiles and restarts, but the results of my checks always stay at 0. I know that the syntax of the command I am using is fine because it executes and returns a proper variable when run manually. In addition when I change my command definition and echo it to a file to check the variables are okay - all is fine there too. Looking through the event viewer on the 2000 machine I see this error - 'NSClient Error: PDH.dll "\\Paging File(_Total)\\%% Usage" - ERROR: ITEM_NOT_VALIDATED'. Has anybody else seen this error at all, its driving me wild !!! Thanks Matthew