diff --git a/src/libsync/discoveryphase.cpp b/src/libsync/discoveryphase.cpp
index 7d1994ebec..ef044b3b0c 100644
--- a/src/libsync/discoveryphase.cpp
+++ b/src/libsync/discoveryphase.cpp
@@ -186,6 +186,18 @@ void DiscoveryPhase::startJob(ProcessDirectoryJob *job)
     job->start();
 }
 
+void DiscoveryPhase::setSelectiveSyncBlackList(const QStringList &list)
+{
+    _selectiveSyncBlackList = list;
+    std::sort(_selectiveSyncBlackList.begin(), _selectiveSyncBlackList.end());
+}
+
+void DiscoveryPhase::setSelectiveSyncWhiteList(const QStringList &list)
+{
+    _selectiveSyncWhiteList = list;
+    std::sort(_selectiveSyncWhiteList.begin(), _selectiveSyncWhiteList.end());
+}
+
 void DiscoveryPhase::scheduleMoreJobs()
 {
     auto limit = qMax(1, _syncOptions._parallelNetworkJobs);
diff --git a/src/libsync/discoveryphase.h b/src/libsync/discoveryphase.h
index 3cd1cb26e2..aa457b65d2 100644
--- a/src/libsync/discoveryphase.h
+++ b/src/libsync/discoveryphase.h
@@ -136,6 +136,10 @@ class DiscoveryPhase : public QObject
     QMap<QString, QString> _renamedItems; // map source -> destinations
     int _currentlyActiveJobs = 0;
 
+    // both must contain a sorted list
+    QStringList _selectiveSyncBlackList;
+    QStringList _selectiveSyncWhiteList;
+
     void scheduleMoreJobs();
 
     bool isInSelectiveSyncBlackList(const QString &path) const;
@@ -167,8 +171,6 @@ public:
     SyncJournalDb *_statedb;
     AccountPtr _account;
     SyncOptions _syncOptions;
-    QStringList _selectiveSyncBlackList;
-    QStringList _selectiveSyncWhiteList;
     ExcludedFiles *_excludes;
     QRegExp _invalidFilenameRx; // FIXME: maybe move in ExcludedFiles
     QStringList _serverBlacklistedFiles; // The blacklist from the capabilities
@@ -177,6 +179,9 @@ public:
 
     void startJob(ProcessDirectoryJob *);
 
+    void setSelectiveSyncBlackList(const QStringList &list);
+    void setSelectiveSyncWhiteList(const QStringList &list);
+
     // output
     QByteArray _dataFingerprint;
 
diff --git a/src/libsync/syncengine.cpp b/src/libsync/syncengine.cpp
index 53fc732c52..10cdacc8a4 100644
--- a/src/libsync/syncengine.cpp
+++ b/src/libsync/syncengine.cpp
@@ -517,8 +517,8 @@ void SyncEngine::startSync()
         _discoveryPhase->_remoteFolder+='/';
     _discoveryPhase->_syncOptions = _syncOptions;
     _discoveryPhase->_shouldDiscoverLocaly = [this](const QString &s) { return shouldDiscoverLocally(s); };
-    _discoveryPhase->_selectiveSyncBlackList = selectiveSyncBlackList;
-    _discoveryPhase->_selectiveSyncWhiteList = _journal->getSelectiveSyncList(SyncJournalDb::SelectiveSyncWhiteList, &ok);
+    _discoveryPhase->setSelectiveSyncBlackList(selectiveSyncBlackList);
+    _discoveryPhase->setSelectiveSyncWhiteList(_journal->getSelectiveSyncList(SyncJournalDb::SelectiveSyncWhiteList, &ok));
     if (!ok) {
         qCWarning(lcEngine) << "Unable to read selective sync list, aborting.";
         syncError(tr("Unable to read from the sync journal."));