Not everyone of my readers will be familiar with MQ Series .. or may know it at all, so if you do not know it, just skip reading, it may not be interesting for you :-)

I recently had to migrate an application from MQ 5.3 up to MQ 7.1.
While that was pretty much straight forward and most of things were easy to accomplish I ended up with an Entry Point Not Found Exception .. all DLLs were available but for whatever reason it just has not worked like it should.

I was using the 2 paramter Version of the GET Call, which fails to link during runtime. After changing that to the 3-param function (that one, which gets the messagesize also) the linking error was gone. No idea why at this point.

After some time, I realised, that there were also a problem with sometimes MQ didn't handle any input messages with the GET call - that was very strange and the problem was solvable by restarting the MQ server - quite weird but because there was a problem with that one queue right before (entry point) I tried to investigate it further.

So, after reading thousands of diskussions, posts and help articles, I were near to giving it up - but when getting desperate someone will try every things he can imagine of. In my case, I just tried the 1-param call. Guess what, that works - the second param was a MessageOptions Object where I told MQ to wait for incoming messages.

So I decided to try the different settings in this Options Object if one of them causes a problem and YES, that's it! It was MQGMO_CONVERT Option which leads to different linking for the GET Call - there was not a single clue about that, but in the end I think it's somehow dumb to not check that right when starting .. pff

So, guys, if everyone is having the same EntryPointNotFoundException when migrating to (or starting to use) MQ Series in their projects then just play around if your Options (if you use them). But First off, check your dlls ;-)