Hi All,
Firstly let me apologise for this, probably ridiculous, question but I’ve given up searching as I don’t even know enough about Unity terms to search for information sensibly.
I’ve not used Unity before and have had a legacy project passed to me so my first priority is to be able to build the code and make sure I have all the source. I’m using 5.5.6f2 and, knowing nothing about the environment, have no intention of changing it until I know what I’m doing.
Anyway - the problem: Previous build evidence has shown that each time the app is built another app is generated e.g. build AppOne and this generates AppOne.exe and AppOne_E.exe. The second of these I think is the “Resolution Dialog”? Running it produces a configuration application allowing graphics and inputs settings to be changed.
How do I generate this second application?
/Stuart
If it’s indeed turning on that dialog that creates the extra exe you can find it in Player Settings - so Edit > Project Settings > Player
There should be a checkbox for show resolution dialog. This dialog has now been removed in the past few versions. See this thread for some info on that: The Display Resolution Dialogue has been deprecated and will be removed in a future version - Unity Engine - Unity Discussions
Thank you very much for the prompt reply.
My “Display Resolution Dialog” is a drop down with Enabled, Disabled and Hidden by Default - none of these options results in the generation of the XXXX_E.exe application.
Would I be right in saying that the resolution dialog simply changes the appropriate registry settings for height and width?
If so then I shouldn’t need to worry too much about not generating the .exe. I just want to make sure I’m picking up from where this project was left off and understand why I don’t need certain bits of it.
HOLD EVERYTHING - I’ve worked it out!!!
For some reason I assumed that this XXX_E.exe was generated by the system AS WELL AS the standard application executable!! I have now discovered it is generated INSTEAD of the standard application AND the “_E” is of the developers making i.e. when building the app they were doing a standard build then another one with the _E postfix on it and the Player Resolution Dialog enabled!!! 
So that’s that issue resolved.
This is worse than noob - this is noob at the deep end lol
(and before you ask, No there isn’t any documentation - there’s a customers existing system to look at and the “we don’t know where the code is but it might be on this laptop here” source code).
Thanking everyone for their patience - and Dave’s reply - but I think this is just the beginning!! 
Glad you got it figured out!