Some agents show as not being connected. Agents are not getting their client policies when requested. Error is shown in log. When the queue is checked at C:\ProgramData\Symantec\SMP\EventQueue\EvtQueue, there are not many files therein.
<event date="06/03/2019 09:55:16.9904725 -04:00" severity="2" hostName="NAME" source="PostEvent" module="w3wp.exe" process="w3wp" pid="2328" thread="242" tickCount="181037187"><![CDATA[Unable to process client request from: 10.10.10.10/POST/8.5.3643.0 (Queue was full, 0x8004200C)]]></event>
<event date="06/03/2019 09:55:34.6101527 -04:00" severity="2" hostName="NAME" source="PostEvent" module="w3wp.exe" process="w3wp" pid="2328" thread="145" tickCount="181054812"><![CDATA[Unable to process client request from: 10.10.10.10/POST/8.5.3643.0 (Failed to register NSE: C:\ProgramData\Symantec\SMP\EventQueue\EvtQueue\04706e4582a54791a72af5fbdcf8223b.nse, source=ff5abeb9-ad20-424c-b8df-c8d163f82079, length=1.22 MB, 0x8004200C)]]></event>
This can be caused if the Evtqueue is manually deleted and many files are currently processing. The database will have data on those files and will have an open thread for them, but they no longer exist, tying up that thread.
To resolve the issue, Stop the Altiris Support Service, and then the Altiris Service. Then run the following SQL in SQL Enterprise Management Studio. NOTE: It is always a good idea to back up the database before running transactions against the database!
truncate table eventqueue
truncate table eventqueueentry
truncate table eventqueueentrymetadata
When complete, restart the Altiris Service, and the Altiris Support Service.