This is how Mac OS has behaved since Yosemite (or maybe even before, haven't checked).
Try opening the Finder, click on say, "Documents" in the left pane and search - you'll see that the search defaults to 'This Mac'.
With all due respect, I am certain that this is not how InDesign worked yesterday before I upgraded to El Capitan.
And even now in El Capitan, if I am in the Finder, and I enter something in the Search field, the default is for it to search the selected folder, per the Finder preferences.
It appears to me that Adobe is probably calling on a standard Apple API for the dialog box and is incorrectly defaulting the scope to This Mac every time.
Is everyone else experiencing this same behavior?
It appears that in El Capitan (OS X 10.11) Mac's native applications like Text Edit, Pages, Numbers, etc. also ignore this Finder Preferences setting 'Search the Current Folder'.
Other Adobe apps like Photoshop & Illustrator also do not honor this setting.
IDCS6 does indeed honor this setting though.
Alas, foolish me, I'm using the very latest InDesign CC 2015 which was just upgraded for compatibility with El Capitan. I don't expect perfection out of the gate, but I really hope Adobe is monitoring these forums and will make the easy fixes to bugs like this one which are nonetheless major impediments to efficiency using Adobe products as a professional.
Rhavi is an Adobe employee...
I am also frustrated with this default "This Mac" when I am in the folder I want to search. I also place hundreds of items each day for the production design work I do.
Is there any way I can get my InDesign to search only the folder I have open when placing an item??????
Is there any solution/workaround to this 'issue' by now? This is still bugging me as hell. It may just be one click from 'This Mac' to the designated folder, but when I have to do it over and over again it's getting very frustrating. Especially if you have a document with hundreds of missing links.
I'm running the latest versions of InDesign (184.108.40.206) and El Capitan (10.11.5) on a MB Pro Mid 2014.