diff --git a/oscar/SleepLib/loader_plugins/prs1_loader.cpp b/oscar/SleepLib/loader_plugins/prs1_loader.cpp
index d9fb0977..9817e481 100644
--- a/oscar/SleepLib/loader_plugins/prs1_loader.cpp
+++ b/oscar/SleepLib/loader_plugins/prs1_loader.cpp
@@ -3597,7 +3597,7 @@ bool PRS1DataChunk::ParseSummaryF3(void)
     if ((it=this->hbdata.find(5)) != this->hbdata.end()) {
         this->duration = (it.value()[1] << 8 ) + it.value()[0];
     } else {
-        qWarning() << "missing summary duration";
+        qWarning() << this->sessionid << "missing summary duration";
     }
 
     return true;
@@ -4024,15 +4024,20 @@ bool PRS1Import::ImportSummary()
     if (!ok) {
         return false;
     }
+    
+    summary_duration = summary->duration;
+
     if (summary->duration == 0) {
         // This does occasionally happen and merely indicates a brief session with no useful data.
         //qDebug() << summary->sessionid << "duration == 0";
-        return false;
+        return true;  // Don't bail for now, since some summary parsers are still very broken, so we want to proceed to events/waveforms.
     }
     
-    summary_duration = summary->duration;
-    session->set_last(qint64(summary->timestamp + summary->duration) * 1000L);
-
+    // Intentionally don't set the session's duration based on the summary duration.
+    // That only happens in PRS1Import::ParseSession() as a last resort.
+    // TODO: Revisit this once summary parsing is reliable.
+    //session->set_last(...);
+    
     return true;
 }
 
@@ -4573,13 +4578,22 @@ bool PRS1Import::ParseSession(void)
 
         if (session->first() > 0) {
             if (session->last() < session->first()) {
-                // Compliance and session parsing both use set_last() to set the session's last timestamp.
-                // Events and waveforms use updateLast().
-                //
-                // if last isn't set, duration couldn't be gained from summary, parsing events or waveforms..
-                // This session is dodgy, so kill it
-                qWarning() << sessionid << "Session last() earlier than first(), downgrading to summary only";
+                // Compliance uses set_last() to set the session's last timestamp, so it
+                // won't reach this point.
+                if (compliance != nullptr) {
+                    qWarning() << sessionid << "compliance didn't set session end?";
+                }
+
+                // Events and waveforms use updateLast() to set the session's last timestamp,
+                // so they should only reach this point if there was a problem parsing them.
+                if (event != nullptr || !wavefile.isEmpty() || !oxifile.isEmpty()) {
+                    qWarning() << sessionid << "Downgrading session to summary only";
+                }
                 session->setSummaryOnly(true);
+
+                // Only use the summary's duration if the session's duration couldn't be
+                // derived from events or waveforms.
+                // TODO: Revisit this once summary parsing is reliable.
                 session->really_set_last(session->first()+(qint64(summary_duration) * 1000L));
             }
             save = true;
diff --git a/oscar/tests/prs1tests.cpp b/oscar/tests/prs1tests.cpp
index 4fb0e854..d0115588 100644
--- a/oscar/tests/prs1tests.cpp
+++ b/oscar/tests/prs1tests.cpp
@@ -126,6 +126,17 @@ static QString ts(qint64 msecs)
     return QDateTime::fromMSecsSinceEpoch(msecs).toString(Qt::ISODate);
 }
 
+static QString dur(qint64 msecs)
+{
+    qint64 s = msecs / 1000L;
+    int h = s / 3600; s -= h * 3600;
+    int m = s / 60; s -= m * 60;
+    return QString("%1:%2:%3")
+        .arg(h, 2, 10, QChar('0'))
+        .arg(m, 2, 10, QChar('0'))
+        .arg(s, 2, 10, QChar('0'));
+}
+
 static QString byteList(QByteArray data, int limit=-1)
 {
     int count = data.size();
@@ -154,6 +165,7 @@ void ChunkToYaml(QFile & file, PRS1DataChunk* chunk)
     out << "  ext: " << chunk->ext << endl;
     out << "  session: " << chunk->sessionid << endl;
     out << "  start: " << ts(chunk->timestamp * 1000L) << endl;
+    out << "  duration: " << dur(chunk->duration * 1000L) << endl;
 
     // hblock for V3 non-waveform chunks
     if (chunk->fileVersion == 3 && chunk->htype == 0) {