diff --git a/oscar/SleepLib/day.cpp b/oscar/SleepLib/day.cpp
index d01e8af2..5e23b09f 100644
--- a/oscar/SleepLib/day.cpp
+++ b/oscar/SleepLib/day.cpp
@@ -107,15 +107,24 @@ void Day::addSession(Session *s)
     auto mi = machines.find(s->type());
     if (mi != machines.end()) {
         if (mi.value() != s->machine()) {
-            qDebug() << "OSCAR can't add session" << s->session() << "to this day record, as it already contains a different machine of the same MachineType";
+            qDebug() << "OSCAR can't add session" << s->session()
+                     << "["+QDateTime::fromTime_t(s->session()).toString("MMM dd, yyyy hh:mm:ss")+"]"
+                     << "from machine" << mi.value()->serial() << "to machine" << s->machine()->serial()
+                     << "to this day record, as it already contains a different machine of the same MachineType" << s->type();
             return;
         }
     } else {
         machines[s->type()] = s->machine();
     }
 
-    sessions.push_back(s);
+    if (s->first() == 0)
+        qWarning() << "Discarding session" << s->session()
+                 << "["+QDateTime::fromTime_t(s->session()).toString("MMM dd, yyyy hh:mm:ss")+"]"
+                 << "from machine" << s->machine()->serial() << "with first=0";
+    else
+        sessions.push_back(s);
 }
+
 EventDataType Day::calcMiddle(ChannelID code)
 {
     int c = p_profile->general->prefCalcMiddle();
diff --git a/oscar/SleepLib/loader_plugins/resmed_loader.cpp b/oscar/SleepLib/loader_plugins/resmed_loader.cpp
index cbf0fe37..e18d10f1 100644
--- a/oscar/SleepLib/loader_plugins/resmed_loader.cpp
+++ b/oscar/SleepLib/loader_plugins/resmed_loader.cpp
@@ -1611,7 +1611,7 @@ int ResmedLoader::Open(const QString & dirpath)
         path = path.section("/", 0, -2);
     }
 
-    // Strip off DATALOG from path, and set newpath to the path contianing DATALOG
+    // Strip off DATALOG from path, and set newpath to the path containing DATALOG
     if (path.endsWith(RMS9_STR_datalog)) {
         newpath = path + "/";
         path = path.section("/", 0, -2);
diff --git a/oscar/SleepLib/machine.cpp b/oscar/SleepLib/machine.cpp
index 8f9ec846..a5ddceca 100644
--- a/oscar/SleepLib/machine.cpp
+++ b/oscar/SleepLib/machine.cpp
@@ -114,8 +114,14 @@ bool Machine::saveSessionInfo()
     out << (int)sessionlist.size();
     for (s = sessionlist.begin(); s != sessionlist.end(); ++s) {
         Session * sess = s.value();
-        out << (quint32) sess->session();
-        out << (bool)(sess->enabled());
+        if (sess->s_first != 0) {
+            out << (quint32) sess->session();
+            out << (bool)(sess->enabled());
+        } else {
+            qWarning() << "Machine::SaveSessionInfo discarding session" << sess->s_session
+                       << "["+QDateTime::fromTime_t(sess->s_session).toString("MMM dd, yyyy hh:mm:ss")+"]"
+                       << "from machine" << serial() << "with first=0";
+        }
 
         //out << sess->m_availableChannels;
     }
@@ -548,7 +554,8 @@ void Machine::setInfo(MachineInfo inf)
 
 const QString Machine::getDataPath()
 {    
-    m_dataPath = p_pref->Get("{home}/Profiles/")+profile->user->userName()+"/"+info.loadername + "_" + (info.serial.isEmpty() ? hexid() : info.serial) + "/";
+    m_dataPath = p_pref->Get("{home}/Profiles/")+profile->user->userName()+"/"+info.loadername + "_"
+                 + (info.serial.isEmpty() ? hexid() : info.serial) + "/";
 
     //if (m_dataPath.isEmpty()) {
  //       m_dataPath = profile->Get("{" + STR_GEN_DataFolder + "}/" + info.loadername + "_" + (info.serial.isEmpty() ? hexid() : info.serial)) + "/";
@@ -740,7 +747,7 @@ bool Machine::SaveSession(Session *sess)
 {
     QString path = getDataPath();
 
-    if (sess->IsChanged()) { sess->Store(path); }
+    if (sess->IsChanged() && sess->first() != 0) { sess->Store(path); }
 
     return true;
 }
diff --git a/oscar/SleepLib/session.cpp b/oscar/SleepLib/session.cpp
index 9615465f..0fc8841a 100644
--- a/oscar/SleepLib/session.cpp
+++ b/oscar/SleepLib/session.cpp
@@ -299,6 +299,13 @@ QDataStream & operator<<(QDataStream & out, const SessionSlice & slice)
 
 bool Session::StoreSummary()
 {
+    if (s_first == 0) {
+        qWarning() << "Session::StoreSummary discarding session" << s_session
+                 << "["+QDateTime::fromTime_t(s_session).toString("MMM dd, yyyy hh:mm:ss")+"]"
+                 << "from machine" << machine()->serial() << "with first=0";
+        return false;
+    }
+
     QString filename = s_machine->getSummariesPath() + QString().sprintf("%08lx.000", s_session);
 
     QFile file(filename);