diff --git a/Action.c b/Action.c
index 5d774587..6e804f68 100644
--- a/Action.c
+++ b/Action.c
@@ -174,8 +174,9 @@ static Htop_Reaction actionSetSortColumn(State* st) {
       char* name = NULL;
       if (fields[i] >= LAST_PROCESSFIELD) {
          DynamicColumn* column = Hashtable_get(dynamicColumns, fields[i]);
-         if (column)
-            name = xStrdup(column->caption ? column->caption : column->name);
+         if (column == NULL)
+            continue;
+         name = xStrdup(column->caption ? column->caption : column->name);
       } else {
          name = String_trim(Process_fields[fields[i]].name);
       }
diff --git a/pcp/PCPDynamicColumn.c b/pcp/PCPDynamicColumn.c
index 141978a7..4051e101 100644
--- a/pcp/PCPDynamicColumn.c
+++ b/pcp/PCPDynamicColumn.c
@@ -287,6 +287,9 @@ void PCPDynamicColumn_writeField(PCPDynamicColumn* this, const Process* proc, Ri
 int PCPDynamicColumn_compareByKey(const PCPProcess* p1, const PCPProcess* p2, ProcessField key) {
    const PCPDynamicColumn* column = Hashtable_get(p1->super.processList->dynamicColumns, key);
 
+   if (column == NULL)
+      return -1;
+
    size_t metric = column->id;
    unsigned int type = PCPMetric_type(metric);