Orphaned photos are photos in your project that haven't been assigned to a specific photo series. Here's what this means:
You won't see orphaned photos in any of the galleries.
They appear before all the other photos in the project.
To sort out orphaned photos, here's what you can do:
If you're still uploading photos, you can set aside the orphaned ones for now.
Tackle any pressing issues before dealing with orphaned photos.
Make sure your project's indexing settings match how you plan to organize photos. Learn more: Project Indexing.
If the orphaned photos don't belong in this project, feel free to delete them.
Try the mis-scan tool (found at the top right of the orphaned photos) to possibly group them into a new series. Learn more: Fix Mis-Scan.
If you recognize the subjects in the orphaned photos, use the move tool (also at the top right) to place them in an existing series. Learn more: Move Photo Series.
Check if the photos remain orphaned due to incomplete processing. If they're recent uploads and the indexing hasn't started, head to the Task Progress meter on the main panel. If it shows indexing at 0, hit "Reindex Project" to kickstart the process.
The Diagnose & Remedy button on your Dashboard and the "Orphan Photos" view tab will turn red to alert you.