diff --git a/src/activities/reader/KOReaderSyncActivity.h b/src/activities/reader/KOReaderSyncActivity.h
index 7f1948d1..dd61ffa5 100644
--- a/src/activities/reader/KOReaderSyncActivity.h
+++ b/src/activities/reader/KOReaderSyncActivity.h
@@ -36,6 +36,9 @@ class KOReaderSyncActivity final : public ActivityWithSubactivity {
         currentSpineIndex(currentSpineIndex),
         currentPage(currentPage),
         totalPagesInSpine(totalPagesInSpine),
+        remoteProgress{},
+        remotePosition{},
+        localProgress{},
         onCancel(std::move(onCancel)),
         onSyncComplete(std::move(onSyncComplete)) {}