Scan to Catalog is one of many ways to add items to your Catalog. Scan to Catalog lets you add large and nested groups of photos from folders on your hard drives.
Go to Catalog> Scan to Catalog 
Optionally, you can choose to include or exclude file extensions.
-Exclude these extensions: All files other than the ones you list will be scanned.
-Include only these extensions: Only the file extensions you list will be scanned.
Once a scan starts, you can start browsing right away, but only indexed photos will be available in searches. The number of photos visible will automatically increase as the indexing completes.
Excluding or Including Folders from Scans
If you want to explicitly include or exclude a folder from scans, you can do so by using Browse and navigating to the folder in the Folder Path. Right-click on the folder and select Include this location when Scanning to Catalog or Exclude this location when Scanning to Catalog.
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