diff --git a/chrome/content/zotero/xpcom/pdfWorker/manager.js b/chrome/content/zotero/xpcom/pdfWorker/manager.js
index 3f54a51c65..9a2d1be9d8 100644
--- a/chrome/content/zotero/xpcom/pdfWorker/manager.js
+++ b/chrome/content/zotero/xpcom/pdfWorker/manager.js
@@ -55,6 +55,8 @@ class PDFWorker {
 			}
 		}
 		this._processingQueue = false;
+		this._worker.terminate();
+		this._worker = null;
 	}
 
 	async _enqueue(fn, isPriority) {