AIR Help was an output offered in Classic versions of RoboHelp up to and including RoboHelp 2019 Classic. However, it had not been developed for several versions as it did not prove popular. I would not recommend starting any new projects with this output. However, if you do need to use it, then here's how it can be merged.
Merged AIR Help
Merged Browser Based AIR Help is created in the same way as Merged WebHelp.
Merged Desktop AIR Help requires a slightly different but straightforward variation.
Merged Desktop AIR Help
The source projects are set up in the same way as described for merged webhelp.
The change in procedure is when you generate. Generate the parent using the AIR Application option. The Output Location can be wherever you want but I suggest you follow the same procedure as with WebHelp and create a separate folder outside of any project.
When the AIR file has been created you will see the dialog below. Click Done. Do not install at this stage.
If you now use Windows Explorer to view the Output Location you will see the AIR file. You will also see a mergedProjects folder has been created with subfolders for each child project defined in the parent. At this stage there will be no content in them except some placeholder files that RoboHelp creates.
Go to each child project in turn to create the AIR output but this is where there is a very important difference.
From the child projects you generate browser based AIR help, even though it is local AIR help that you want. Because you will select Browser Based Help as the Output Type in the dialog shown in Step 1, the Start Page field will be enabled. Browse to the relevant child project subfolder created when you generate the parent and generate the output to that folder.
When you have generated all the child projects, go back to the Parent and generate that again. When the dialog shown in Step 3 appears, click Install.
The installed AIR help will display all the projects.
The TOC, Search and Index worked as expected in a simple test and removing one of the child project outputs that you will find in Program Files worked in the same way as removing a child folder from merged webhelp. Please note though that I did not test removing child projects extensively.
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