diff --git a/modules/sync/syncs/httpsynchronization.cpp b/modules/sync/syncs/httpsynchronization.cpp
index 011e164a84..25b8b5c2b9 100644
--- a/modules/sync/syncs/httpsynchronization.cpp
+++ b/modules/sync/syncs/httpsynchronization.cpp
@@ -57,6 +57,10 @@ HttpSynchronization::HttpSynchronization(
     const std::vector<std::string>& synchronizationRepositories
 )
     : openspace::ResourceSynchronization(dict)
+    , _nTotalBytesKnown(false)
+    , _nTotalBytes(0)
+    , _nSynchronizedBytes(0)
+    , _shouldCancel(false)
     , _synchronizationRoot(synchronizationRoot)
     , _synchronizationRepositories(synchronizationRepositories)
 {
diff --git a/modules/sync/syncs/httpsynchronization.h b/modules/sync/syncs/httpsynchronization.h
index 50af99c19b..61374fd1ae 100644
--- a/modules/sync/syncs/httpsynchronization.h
+++ b/modules/sync/syncs/httpsynchronization.h
@@ -59,11 +59,11 @@ private:
     bool hasSyncFile();
     void createSyncFile();
 
-    std::atomic_bool _nTotalBytesKnown = false;
-    std::atomic_size_t _nTotalBytes = 0;
-    std::atomic_size_t _nSynchronizedBytes = 0;
+    std::atomic_bool _nTotalBytesKnown;
+    std::atomic_size_t _nTotalBytes;
+    std::atomic_size_t _nSynchronizedBytes;
 
-    std::atomic_bool _shouldCancel = false;
+    std::atomic_bool _shouldCancel;
     std::string _identifier;
     int _version;
     std::string _synchronizationRoot;