diff --git a/lib/index/mu-indexer.cc b/lib/index/mu-indexer.cc
index 2dfa17d5..9790ff36 100644
--- a/lib/index/mu-indexer.cc
+++ b/lib/index/mu-indexer.cc
@@ -284,7 +284,7 @@ Indexer::Private::cleanup()
 void
 Indexer::Private::scan_worker()
 {
-	progress_ = {};
+	progress_.reset();
 
 	if (conf_.scan) {
 		g_debug("starting scanner");
@@ -410,7 +410,7 @@ Indexer::is_running() const
 	return priv_->state_ != IndexState::Idle;
 }
 
-Indexer::Progress
+const Indexer::Progress&
 Indexer::progress() const
 {
 	priv_->progress_.running = priv_->state_ == IndexState::Idle ? false : true;
diff --git a/lib/index/mu-indexer.hh b/lib/index/mu-indexer.hh
index 2df7f1c6..bf318b02 100644
--- a/lib/index/mu-indexer.hh
+++ b/lib/index/mu-indexer.hh
@@ -1,5 +1,5 @@
 /*
-** Copyright (C) 2021 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+** Copyright (C) 2022 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 **
 ** This program is free software; you can redistribute it and/or modify it
 ** under the terms of the GNU General Public License as published by the
@@ -20,6 +20,7 @@
 #ifndef MU_INDEXER_HH__
 #define MU_INDEXER_HH__
 
+#include <atomic>
 #include <memory>
 #include <chrono>
 
@@ -88,20 +89,26 @@ public:
 
 	// Object describing current progress
 	struct Progress {
-		bool   running{}; /**< Is an index operation in progress? */
-		size_t checked{}; /**< Number of messages checked for changes */
-		size_t updated{}; /**< Number of messages (re)parsed &  added/updated to store */
-		size_t removed{}; /**< Number of message removed from store */
+		void reset()
+		{
+			running = false;
+			checked = updated = removed = 0;
+		}
+
+		std::atomic<bool>   running{}; /**< Is an index operation in progress? */
+		std::atomic<size_t> checked{}; /**< Number of messages checked for changes */
+		std::atomic<size_t> updated{}; /**< Number of messages (re)parsed/added/updated */
+		std::atomic<size_t> removed{}; /**< Number of message removed from store */
 	};
 
 	/**
 	 * Get an object describing the current progress. The progress object
-	 * describes the most recent indexing job, and is reset up a fresh
+	 * describes the most recent indexing job, and is reset upon a fresh
 	 * start().
 	 *
 	 * @return a progress object.
 	 */
-	Progress progress() const;
+	const Progress& progress() const;
 
 private:
 	struct Private;