Look for the Document Preferences dropdown (gear icon) or right-click inside any citation. Select "Relink Citations..."
When you click "Refresh," Zotero reads these coordinates, looks up the current metadata in your database, and builds the formatted citation. how to relink citations in zotero
For the remaining 10%—especially those with corrupted field codes or deleted items—the solution is discipline: maintain version control of your document, never delete sources mid-project, and always keep a "live" backup copy before unlinking. Look for the Document Preferences dropdown (gear icon)