My unsigned application has an mdimporter. In 10.14, it has stopped working, and the error messages suggest a code signature issue (see below). I have not found any documentation on the impact of code signatures on mdimporters. Is this a macOS bug, or am I supposed to change something?
A similar problem has been reported for EverNote.
https://discussion.evernote.com/topic/116651-en-752-spotlight-not-working-errors-w-mdimporter/
The logged error messages:
code signature in ... not valid for use in process using Library Validation: mapped file has no Team ID and is not a platform binary (signed with custom identity or adhoc?)
Cannot find function pointer MetadataImporterPluginFactory for factory C8BC68DA-C20C-4742-9BE6-D438C0D48ED2 in CFBundle/CFPlugIn 0x7fb2e2d076c0 <...> (bundle, not loaded)