Symantec Management Platform (Notification Server)

I created a dynamic filter.  When I view it under Manage - Filters I see a total count of 79 computers.  I have applied a pcanywhere policy to it and when I open the policy it shows a total count of 59 computers.  Any tips on troubleshooting this issue?

I was looking through the error logs and found this relating the filter in question:

Log File Name: C:\ProgramData\Symantec\SMP\Logs\a.log
Priority: 2
Date: 12/9/2011 7:14:15 PM
Tick Count: 261852249
Host Name:
Process: AeXSvc (10640)
Thread ID: 78
Module: AeXSVC.exe
Source: Altiris.NS.StandardItems.Collection.NSDataSrcBasedResourceCollection.DeltaUpdateMembership
Description: Unexpected exception has occurred during the construction of the SQL for delta collection update for '****FILTER NAME***** (12397b0a-ffeb-48a9-bc71-6718d462ae66)'. Full update is run instead.
**CEDUrlStart** :http://entced.symantec.com/entt?product=SMP&version=7.1.6851.0&language=en&module=b9RbreYix02ln06boPs4ip15Rea15BgcsmAJmNYCD2VEzxO/3Rb6Z+ivMh/KXJfzGfvSZnAseEpP8k/dqRm8Cw==&error=1273128720&build=**CEDUrlEnd**

( Exception Details: Altiris.DataSource.Exceptions.DataSourceSchemaException: Failed to perform a delta collection membership update for the resource collection '****FILTER NAME****** (12397b0a-ffeb-48a9-bc71-6718d462ae66)'. At least one scoping field must be selected.
   at Altiris.NS.StandardItems.Collection.NSDataSrcBasedResourceCollection.DeltaUpdateMembership() )
( Exception logged from:
   at Altiris.Diagnostics.Logging.EventLog.ReportException(Int32 severity, String strMessage, String category, Exception exception)
   at Altiris.NS.Logging.EventLog.ReportException(Int32 severity, String strMessage, String category, Exception exception)
   at Altiris.NS.StandardItems.Collection.NSDataSrcBasedResourceCollection.DeltaUpdateMembership()
   at Altiris.NS.StandardItems.Collection.NSDataSrcBasedResourceCollection.UpdateMembershipCore(ICollectionUpdateMessage updateMessage)
   at Altiris.NS.StandardItems.Collection.NSResourceCollectionBase.<>c__DisplayClass4.<UpdateMembership>b__0(IDatabaseContext ctx)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetryHelper(Int32 retries, Boolean inTransaction, Getter`1 getContext, Action`1 action, Action`1 retry)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetry(Int32 retries, Boolean startNewTransaction, IsolationLevel isolationLevel, Boolean independentContext, Action`1 action, Action`1 retry)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetry(Int32 retries, Boolean startNewTransaction, Action`1 action, Action`1 retry)
   at Altiris.NS.ContextManagement.DatabaseContext.PerformWithDeadlockRetry(Int32 retries, Action`1 action, Action`1 retry)
   at Altiris.NS.StandardItems.Collection.NSResourceCollectionBase.UpdateMembership(ICollectionUpdateMessage updateMessage)
   at Altiris.NS.StandardItems.Collection.DeltaCollectionUpdateSchedule.DeltaUpdateCollections(GuidCollection collectionGuids, DateTime lastRunTime)
   at Altiris.NS.StandardItems.Collection.DeltaCollectionUpdateSchedule.OnSchedule_Impl()
   at Altiris.NS.StandardItems.Collection.DeltaCollectionUpdateSchedule.OnSchedule(String identifier)
   at Altiris.NS.StandardItems.ContainerUpdateSchedule.<>c__DisplayClass2.<RunFilterDeltaUpdate>b__0(IDatabaseContext ctx)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetryHelper(Int32 retries, Boolean inTransaction, Getter`1 getContext, Action`1 action, Action`1 retry)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetry(Int32 retries, Boolean startNewTransaction, IsolationLevel isolationLevel, Boolean independentContext, Action`1 action, Action`1 retry)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetry(Int32 retries, Boolean startNewTransaction, Action`1 action, Action`1 retry)
   at Altiris.Database.DatabaseContext`1.PerformWithDeadlockRetry(Int32 retries, Boolean startNewTransaction, Action`1 action)
   at Altiris.NS.ContextManagement.DatabaseContext.PerformWithDeadlockRetry(Int32 retries, Action`1 action)
   at Altiris.NS.StandardItems.ContainerUpdateSchedule.RunFilterDeltaUpdate(String identifier)
   at Altiris.NS.StandardItems.ContainerUpdateSchedule.RunDeltaUpdate(String identifier)
   at Altiris.NS.StandardItems.ContainerUpdateSchedule.OnSchedule(String identifier)
   at Altiris.NS.Scheduling.ScheduleService.ProcessSchedule(String scheduleId)
   at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
   at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)
   at System.Runtime.Remoting.Messaging.ServerObjectTerminatorSink.SyncProcessMessage(IMessage reqMsg)
   at System.Runtime.Remoting.Lifetime.LeaseSink.SyncProcessMessage(IMessage msg)
   at System.Runtime.Remoting.Messaging.ServerContextTerminatorSink.SyncProcessMessage(IMessage reqMsg)
   at System.Runtime.Remoting.Channels.CrossContextChannel.SyncProcessMessageCallback(Object[] args)
   at System.Runtime.Remoting.Channels.ChannelServices.DispatchMessage(IServerChannelSinkStack sinkStack, IMessage msg, IMessage& replyMsg)
   at System.Runtime.Remoting.Channels.BinaryServerFormatterSink.ProcessMessage(IServerChannelSinkStack sinkStack, IMessage requestMsg, ITransportHeaders requestHeaders, Stream requestStream, IMessage& responseMsg, ITransportHeaders& responseHeaders, Stream& responseStream)
   at System.Runtime.Remoting.Channels.SoapServerFormatterSink.ProcessMessage(IServerChannelSinkStack sinkStack, IMessage requestMsg, ITransportHeaders requestHeaders, Stream requestStream, IMessage& responseMsg, ITransportHeaders& responseHeaders, Stream& responseStream)
   at System.Runtime.Remoting.MetadataServices.SdlChannelSink.ProcessMessage(IServerChannelSinkStack sinkStack, IMessage requestMsg, ITransportHeaders requestHeaders, Stream requestStream, IMessage& responseMsg, ITransportHeaders& responseHeaders, Stream& responseStream)
   at System.Runtime.Remoting.Channels.Tcp.TcpServerTransportSink.ServiceRequest(Object state)
   at System.Runtime.Remoting.Channels.SocketHandler.ProcessRequestNow()
   at System.Runtime.Remoting.Channels.SocketHandler.BeginReadMessageCallback(IAsyncResult ar)
   at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Net.ContextAwareResult.Complete(IntPtr userToken)
   at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
   at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)
 )
( Extra Details:  Type=Altiris.DataSource.Exceptions.DataSourceSchemaException Src=Altiris.NS.StandardItems )
 

like Computers with psAnywhere Plug-in installed?

Or what happens if you update the filter, does the number of PCs change?

I didn't realize that my filter was pulling in workstations that aren't managed.  Any of these that don't have pcAnwhere installed won't show up as targets.  Thanks for your help.