Seeing an error about “nothing to sync” (or “nothing to scan”, in earlier versions of PhotoStructure)?
Your PhotoStructure library has a database that needs to be periodically synchronized with your filesystem. This synchronization process is described here.
By default, PhotoStructure will first sync your originals directory (which defaults to the root directory of your library). This can be disabled by setting syncLibraryFirst=false. Read about settings here.
Second, if you selected “Scan all directories”, or included any directories in the “Where else are your photos and videos?” settings section, these will be synchronized.
Finally, if you’ve changed the setting syncLibraryLast=true, your library will be synchronized.
If syncLibraryFirst=false and syncLibraryLast=false, know that your library won’t ever be synchronized, which will cause PhotoStructure’s deduplication and automatic organization to be incorrect.