Content (in the global folder or outside a site hierarchy) will be indexed in Find against whichever site has a wildcard host binding set up in Episerver. It sounds like you don't have one site configured this way.
See this post for more information - https://world.episerver.com/blogs/Johan-Bjornfot/Dates1/2013/12/Multisite-feature-in-EPiServer-75/
Thanks a lot Mark - this was the solution I was looking for.
@robert Did you find a solution for your problem, because we have the same problem when Find index job runs.
I am having an issue indexing PDFs which resides in global asset folder: they are not indexed.
What is the default behavior when Episerver Find indexes global assets? (which url are they being index with?)
Have anyone any work arounds for indexing global assets running multi-sites?
I hoped I could point to a "default site" to resolve a full URL for a PDF - but seems like, it does not exist out-of-the-box.
What I do get: an exception registered in the log when running the indexer.
I think the problem is, that Find cannot index items, such as PDFs, which reside in global assets folder when running in multi-site-environment.
We have multi-site setup with sites like "SiteA.com" and "SiteB.com". If I try to download a PDF from global asset via Episerver admin interface, it will be downloaded from the context/site I am currently on.
But, when indexing (EPiServer Find Content Indexing Job), I am not on any site - and I am guessing it breaks.
Note: It works for PDFs in "For this site".
What the message in the "History"-tab tells me:
An exception occurred while indexing content 1890: Exception has been thrown by the target of an invocation. (see log for more information)
What the error-log tells me:
2017-07-03 17:02:27,541  ERROR EPiServer.Find.Cms.ContentIndexer: WIN-XXXXXXXX: An exception occurred while indexing content 1890: Exception has been thrown by the target of an invocation.
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at EPiServer.Find.Cms.CmsUnifiedSearchSetUp.ContentExternalUrl(ContentReference contentLink, CultureInfo contentLanguage, Boolean absoluteUrl)
at EPiServer.Find.Cms.CmsUnifiedSearchSetUp.GetContentUrl(ContentReference contentLink, String language)
--- End of inner exception stack trace ---
It seems that something is null, when call ContentExternalUrl ..