diff --git a/oscar/SleepLib/loader_plugins/prs1_loader.cpp b/oscar/SleepLib/loader_plugins/prs1_loader.cpp
index f0daf26e..d1ebb968 100644
--- a/oscar/SleepLib/loader_plugins/prs1_loader.cpp
+++ b/oscar/SleepLib/loader_plugins/prs1_loader.cpp
@@ -891,7 +891,7 @@ void PRS1Loader::ScanFiles(const QStringList & paths, int sessionid_base, Machin
 
     QDateTime datetime;
 
-    qint64 ignoreBefore = p_profile->session->ignoreOlderSessionsDate().toSecsSinceEpoch();
+    qint64 ignoreBefore = p_profile->session->ignoreOlderSessionsDate().toMSecsSinceEpoch()/1000;
     bool ignoreOldSessions = p_profile->session->ignoreOlderSessions();
     QSet<SessionID> skipped;
 
@@ -1015,8 +1015,8 @@ void PRS1Loader::ScanFiles(const QStringList & paths, int sessionid_base, Machin
                 }
                 if (ignoreOldSessions && chunk->timestamp < ignoreBefore) {
                     qDebug().noquote() << relativePath(path) << "skipping session" << chunk_sid << ":"
-                        << QDateTime::fromSecsSinceEpoch(chunk->timestamp).toString() << "older than"
-                        << QDateTime::fromSecsSinceEpoch(ignoreBefore).toString();
+                        << QDateTime::fromMSecsSinceEpoch(chunk->timestamp*1000).toString() << "older than"
+                        << QDateTime::fromMSecsSinceEpoch(ignoreBefore*1000).toString();
                     skipped += chunk_sid;
                     delete chunk;
                     continue;
@@ -7683,14 +7683,14 @@ QList<PRS1DataChunk *> PRS1Import::CoalesceWaveformChunks(QList<PRS1DataChunk *>
     // This won't be perfect, since any coalesced chunks starting after midnight of the threshhold
     // date will also be imported, but those should be relatively few, and tolerable imprecision.
     QList<PRS1DataChunk *> coalescedAndFiltered;
-    qint64 ignoreBefore = p_profile->session->ignoreOlderSessionsDate().toSecsSinceEpoch();
+    qint64 ignoreBefore = p_profile->session->ignoreOlderSessionsDate().toMSecsSinceEpoch()/1000;
     bool ignoreOldSessions = p_profile->session->ignoreOlderSessions();
 
     for (auto & chunk : coalesced) {
         if (ignoreOldSessions && chunk->timestamp < ignoreBefore) {
             qWarning().noquote() << relativePath(chunk->m_path) << "skipping session" << chunk->sessionid << ":"
-                << QDateTime::fromSecsSinceEpoch(chunk->timestamp).toString() << "older than"
-                << QDateTime::fromSecsSinceEpoch(ignoreBefore).toString();
+                << QDateTime::fromMSecsSinceEpoch(chunk->timestamp*1000).toString() << "older than"
+                << QDateTime::fromMSecsSinceEpoch(ignoreBefore*1000).toString();
             continue;
         }
         coalescedAndFiltered.append(chunk);
diff --git a/oscar/oscar.pro b/oscar/oscar.pro
index b9d6909b..79fa49c2 100644
--- a/oscar/oscar.pro
+++ b/oscar/oscar.pro
@@ -487,6 +487,10 @@ memdebug {
     !win32 {  # add memory checking on Linux and macOS debug builds
         QMAKE_CFLAGS += -g -Werror -fsanitize=address -fno-omit-frame-pointer -fno-common -fsanitize-address-use-after-scope
         QMAKE_CXXFLAGS += -g -Werror -fsanitize=address -fno-omit-frame-pointer -fno-common -fsanitize-address-use-after-scope
+        lessThan(QT_MAJOR_VERSION,5)|lessThan(QT_MINOR_VERSION,9) {
+            QMAKE_CFLAGS -= -fsanitize-address-use-after-scope
+            QMAKE_CXX_FLAGS -= -fsanitize-address-use-after-scope
+        }
         QMAKE_LFLAGS += -fsanitize=address
     }
 }