diff --git a/common/base-typemaps.i b/common/base-typemaps.i
index 62c8f96f61..e9f7ac0ec8 100644
--- a/common/base-typemaps.i
+++ b/common/base-typemaps.i
@@ -21,6 +21,7 @@
  * Boston, MA  02110-1301,  USA       gnu@gnu.org                   *
  *                                                                  *
 \********************************************************************/
+%include "constraints.i"
 
 typedef void * gpointer; // Not sure why SWIG doesn't figure this out.
 %typemap(newfree) gchar * "g_free($1);"
@@ -93,22 +94,25 @@ typedef char gchar;
 %typemap(out) struct tm * {
     SCM tm = scm_c_make_vector(11, SCM_UNDEFINED);
     struct tm* t = $1;
-    SCM_SIMPLE_VECTOR_SET(tm, 0, scm_from_int(t->tm_sec));
-    SCM_SIMPLE_VECTOR_SET(tm, 1, scm_from_int(t->tm_min));
-    SCM_SIMPLE_VECTOR_SET(tm, 2, scm_from_int(t->tm_hour));
-    SCM_SIMPLE_VECTOR_SET(tm, 3, scm_from_int(t->tm_mday));
-    SCM_SIMPLE_VECTOR_SET(tm, 4, scm_from_int(t->tm_mon));
-    SCM_SIMPLE_VECTOR_SET(tm, 5, scm_from_int(t->tm_year));
-    SCM_SIMPLE_VECTOR_SET(tm, 6, scm_from_int(t->tm_wday));
-    SCM_SIMPLE_VECTOR_SET(tm, 7, scm_from_int(t->tm_yday));
-    SCM_SIMPLE_VECTOR_SET(tm, 8, scm_from_int(t->tm_isdst));
+    if (t != NULL)
+    {
+        SCM_SIMPLE_VECTOR_SET(tm, 0, scm_from_int(t->tm_sec));
+        SCM_SIMPLE_VECTOR_SET(tm, 1, scm_from_int(t->tm_min));
+        SCM_SIMPLE_VECTOR_SET(tm, 2, scm_from_int(t->tm_hour));
+        SCM_SIMPLE_VECTOR_SET(tm, 3, scm_from_int(t->tm_mday));
+        SCM_SIMPLE_VECTOR_SET(tm, 4, scm_from_int(t->tm_mon));
+        SCM_SIMPLE_VECTOR_SET(tm, 5, scm_from_int(t->tm_year));
+        SCM_SIMPLE_VECTOR_SET(tm, 6, scm_from_int(t->tm_wday));
+        SCM_SIMPLE_VECTOR_SET(tm, 7, scm_from_int(t->tm_yday));
+        SCM_SIMPLE_VECTOR_SET(tm, 8, scm_from_int(t->tm_isdst));
 %#ifdef HAVE_STRUCT_TM_GMTOFF
-    SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(t->tm_gmtoff));
-    SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string(t->tm_zone?t->tm_zone:"Unset"));
+        SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(t->tm_gmtoff));
+        SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string(t->tm_zone?t->tm_zone:"Unset"));
 %#else
-    SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(0));
-    SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string("GMT"));
+        SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(0));
+        SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string("GMT"));
 %#endif
+     }
     $result = tm;
  }
  
@@ -117,22 +121,25 @@ typedef char gchar;
 %typemap(argout) struct tm * {
     struct tm* t = $1;
     SCM tm = $input;
-    SCM_SIMPLE_VECTOR_SET(tm, 0, scm_from_int(t->tm_sec));
-    SCM_SIMPLE_VECTOR_SET(tm, 1, scm_from_int(t->tm_min));
-    SCM_SIMPLE_VECTOR_SET(tm, 2, scm_from_int(t->tm_hour));
-    SCM_SIMPLE_VECTOR_SET(tm, 3, scm_from_int(t->tm_mday));
-    SCM_SIMPLE_VECTOR_SET(tm, 4, scm_from_int(t->tm_mon));
-    SCM_SIMPLE_VECTOR_SET(tm, 5, scm_from_int(t->tm_year));
-    SCM_SIMPLE_VECTOR_SET(tm, 6, scm_from_int(t->tm_wday));
-    SCM_SIMPLE_VECTOR_SET(tm, 7, scm_from_int(t->tm_yday));
-    SCM_SIMPLE_VECTOR_SET(tm, 8, scm_from_int(t->tm_isdst));
+    if (t == NULL)
+    {
+        SCM_SIMPLE_VECTOR_SET(tm, 0, scm_from_int(t->tm_sec));
+        SCM_SIMPLE_VECTOR_SET(tm, 1, scm_from_int(t->tm_min));
+        SCM_SIMPLE_VECTOR_SET(tm, 2, scm_from_int(t->tm_hour));
+        SCM_SIMPLE_VECTOR_SET(tm, 3, scm_from_int(t->tm_mday));
+        SCM_SIMPLE_VECTOR_SET(tm, 4, scm_from_int(t->tm_mon));
+        SCM_SIMPLE_VECTOR_SET(tm, 5, scm_from_int(t->tm_year));
+        SCM_SIMPLE_VECTOR_SET(tm, 6, scm_from_int(t->tm_wday));
+        SCM_SIMPLE_VECTOR_SET(tm, 7, scm_from_int(t->tm_yday));
+        SCM_SIMPLE_VECTOR_SET(tm, 8, scm_from_int(t->tm_isdst));
 %#ifdef HAVE_STRUCT_TM_GMTOFF
-    SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(t->tm_gmtoff));
-    SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string(t->tm_zone?t->tm_zone:"Unset"));
+        SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(t->tm_gmtoff));
+        SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string(t->tm_zone?t->tm_zone:"Unset"));
 %#else
-    SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(0));
-    SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string("GMT"));
+        SCM_SIMPLE_VECTOR_SET(tm, 9, scm_from_long(0));
+        SCM_SIMPLE_VECTOR_SET(tm, 10, scm_from_locale_string("GMT"));
 %#endif
+     }
  }
 
 %define GLIST_HELPER_INOUT(ListType, ElemSwigType)
diff --git a/gnucash/gnome-utils/gnc-cell-renderer-date.c b/gnucash/gnome-utils/gnc-cell-renderer-date.c
index 210c04ad70..e47a386511 100644
--- a/gnucash/gnome-utils/gnc-cell-renderer-date.c
+++ b/gnucash/gnome-utils/gnc-cell-renderer-date.c
@@ -437,7 +437,8 @@ gcrd_time2dmy (time64 raw_time, gint *day, gint *month, gint *year)
     struct tm * timeinfo;
   
     timeinfo = gnc_localtime (&raw_time);
- 
+    if (timeinfo == NULL)
+        return FALSE;
     *day = timeinfo->tm_mday;
     *month = timeinfo->tm_mon + 1;
     *year = timeinfo->tm_year + 1900;
diff --git a/gnucash/gnome/assistant-loan.c b/gnucash/gnome/assistant-loan.c
index 9ed325755e..26370f5c38 100644
--- a/gnucash/gnome/assistant-loan.c
+++ b/gnucash/gnome/assistant-loan.c
@@ -1091,11 +1091,14 @@ loan_info_page_save( GtkAssistant *assistant, gpointer user_data )
 
         tmpTT = gnc_date_edit_get_date( ldd->prmStartDateGDE );
         tmpTm = gnc_localtime ( &tmpTT );
-        g_date_set_dmy( ldd->ld.startDate,
-                        tmpTm->tm_mday,
-                        (tmpTm->tm_mon + 1),
-                        (1900 + tmpTm->tm_year) );
-	gnc_tm_free (tmpTm);
+        if (tmpTm)
+        {
+            g_date_set_dmy( ldd->ld.startDate,
+                            tmpTm->tm_mday,
+                            (tmpTm->tm_mon + 1),
+                            (1900 + tmpTm->tm_year) );
+            gnc_tm_free (tmpTm);
+        }
     }
 
     /* len / periods */
diff --git a/libgnucash/engine/Transaction.c b/libgnucash/engine/Transaction.c
index 5fc7c7eeb1..17e019e8cf 100644
--- a/libgnucash/engine/Transaction.c
+++ b/libgnucash/engine/Transaction.c
@@ -2426,10 +2426,13 @@ xaccTransGetDatePostedGDate (const Transaction *trans)
               */
              time64 time = xaccTransGetDate(trans);
              struct tm *stm = gnc_gmtime(&time);
-             g_date_set_dmy(&result, stm->tm_mday,
-                            (GDateMonth)(stm->tm_mon + 1),
-                            stm->tm_year + 1900);
-             free(stm);
+             if (stm)
+             {
+                 g_date_set_dmy(&result, stm->tm_mday,
+                                (GDateMonth)(stm->tm_mon + 1),
+                                stm->tm_year + 1900);
+                 free(stm);
+             }
         }
     }
     return result;