Sporadically, builds do not finish. But no processes related to the build are running.
Requesting to stop the build does not help either.
As a result, new builds for these hanging build configuration cannot be started anymore.
The only way to clean up is the restart the QuickBuild server. As we are using QB also for long running load test builds (lasting multiple days), this is very annoying.

Here is the end of the log output of the build (taken multiple hours after the last log entry). Note that the step TS01 has no explicit post-execution action.

08:44:53,012 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TBuilder@ska-wn-build01:8810] INFO - Executing post-execute action...
08:44:53,053 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - Checking step execute condition...
08:44:53,053 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - Step execute condition satisfied, executing...
08:44:54,069 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - Executing pre-execute action...
08:44:54,069 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - Running step...
08:44:54,069 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - The report dir: D:\quickbuild-4.0.88\workspace\root\xserver\servers\xlocate\module\trunk\vc10\x86\target does not exists.
08:44:54,069 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TxSUnitReport@ska-wn-build01:8810] INFO - Executing post-execute action...
08:44:54,109 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TPublisher@ska-wn-build01:8810] INFO - Checking step execute condition...
08:44:54,114 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>TPublisher@ska-wn-build01:8810] INFO - Step execute condition not satisfied, step will be skipped.
08:44:54,140 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>Tsonar@ska-wn-build01:8810] INFO - Checking step execute condition...
08:44:54,140 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86>Tsonar@ska-wn-build01:8810] INFO - Step execute condition not satisfied, step will be skipped.
08:44:54,153 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10>TS03?OSPlat=x86@ska-wn-build01:8810] INFO - Executing post-execute action...
08:44:54,184 [master>TTrunk>TS00>TS01?OSName=Windows_NT>TS02?Target_Os=win&Toolset=vc10@ska-wn-build01:8810] INFO - Executing post-execute action...
08:44:54,231 [master>TTrunk>TS00>TS01?OSName=Windows_NT@ska-wn-build01:8810] INFO - Executing post-execute action...