Created On:  24 July 2012

Problem:

By default DevPartner does not enable the merge of coverage files from two different executables.

Resolution:

There is a undocumented switch that can be used:  
The  /a switch
Sample test run
C:\test>nmmerge /a /d . /m output.dpmrg  c:\test\HelloWorld1.dpcov c:\test\HelloWorld2.dpcov
Loading c:\test\HelloWorld1.dpcov...
Done
Merging c:\test\HelloWorld2.dpcov...
Done
Incident #2583572