The app won’t index my library
Make sure your Zotero client is completely closed
before you start indexing. The app reads Zotero’s local SQLite database
(zotero.sqlite) directly, and Zotero locks that file while
it’s open — so if Zotero is running, the app can’t access your library
and indexing will fail.
Quit Zotero fully (not just close the window), then start indexing again. See Indexing Your Library for how indexing works.