sp_cop crashes upon start - Error: "Unknown problem" (4255942)

sp_cop will not start and the following error appears in the event_log:

Error: Unknown problem - exiting [sp_cop/749744]
Error: Shutting down SharePlex: Unknown problem [sp_cop/749744]
sp_cop was shutdown using 'abort' flag
SharePlex was shutdown
Error: Shutting down SharePlex: Unknown problem [sp_cop/749744]

trace_log with SP_COP_DEBUG 0xffffffff shows the following
08/23/06 15:50 Debug: internal_shudown(3) [sp_cop/749744]
08/23/06 15:50 Debug: cop_shutdown(3) [sp_cop/749744]
08/23/06 15:50 Debug: requestor 0x3171a738 [sp_cop/749744]
08/23/06 15:50 Debug: abort=1 keepcap=0 [sp_cop/749744]
08/23/06 15:50 Debug: shutdown obj pass 1 [sp_cop/749744]
08/23/06 15:50 Debug: obj_shutdown(Q, abort=1) pid= [sp_cop/749744]
08/23/06 15:50 Debug: shutdown obj pass 1 [sp_cop/749744]
08/23/06 15:50 Debug: obj_shutdown(PP, abort=1) pid= [sp_cop/749744]
08/23/06 15:50 Debug: shutdown obj pass 1 [sp_cop/749744]

This can happen for several reasons:

1. There are many post queues and each cannot obtain required shared memory. The solution is to either decrease the number of queues or decrease the amount of memory required for each queue. The parameter that controls post queue memory size is SP_QUE_POST_SHMSIZE. Decrease this parameter by 1/2 or 2/3. For example, if SP_QUE_POST_SHMSIZE is at default 32M, then set it to 8MB.

2. sp_cop cannot grab specific memory segments because they are hung. See Solution 2663 - "Hung semaphore and/or memory segment" in the Knowledgebase: https://support.quest.com/SUPPORT/index?page=solution&id=SOL2663 for information on how to remove hung shared memory segments.