diff --git a/core/app.py b/core/app.py
index b2a7ad51..481ec40e 100644
--- a/core/app.py
+++ b/core/app.py
@@ -98,12 +98,17 @@ class DupeGuru(RegistrableApplication, Broadcaster):
         except EnvironmentError:
             return None
     
+    def _results_changed(self):
+        self.selected_dupes = [d for d in self.selected_dupes
+            if self.results.get_group_of_duplicate(d) is not None]
+        self.notify('results_changed')
+    
     def _job_completed(self, jobid):
         # Must be called by subclasses when they detect that an async job is completed.
         if jobid == JOB_SCAN:
-            self.notify('results_changed')
+            self._results_changed()
         elif jobid in (JOB_LOAD, JOB_MOVE, JOB_DELETE):
-            self.notify('results_changed')
+            self._results_changed()
             self.notify('problems_changed')
     
     @staticmethod
@@ -171,7 +176,7 @@ class DupeGuru(RegistrableApplication, Broadcaster):
             filter = escape(filter, set('()[]\\.|+?^'))
             filter = escape(filter, '*', '.')
         self.results.apply_filter(filter)
-        self.notify('results_changed')
+        self._results_changed()
     
     def clean_empty_dirs(self, path):
         if self.options['clean_empty_dirs']:
@@ -316,7 +321,7 @@ class DupeGuru(RegistrableApplication, Broadcaster):
     
     def remove_marked(self):
         self.results.perform_on_marked(lambda x:None, True)
-        self.notify('results_changed')
+        self._results_changed()
     
     def remove_selected(self):
         self.remove_duplicates(self.selected_dupes)
@@ -356,7 +361,7 @@ class DupeGuru(RegistrableApplication, Broadcaster):
         if not self.directories.has_any_file():
             raise NoScannableFileError()
         self.results.groups = []
-        self.notify('results_changed')
+        self._results_changed()
         self._start_job(JOB_SCAN, do)
     
     def toggle_selected_mark_state(self):
diff --git a/core/results.py b/core/results.py
index b4c1ea01..a0e871b0 100644
--- a/core/results.py
+++ b/core/results.py
@@ -259,11 +259,14 @@ class Results(Markable):
             group = self.get_group_of_duplicate(dupe)
             if dupe not in group.dupes:
                 return
+            ref = group.ref
             group.remove_dupe(dupe, False)
+            del self.__group_of_duplicate[dupe]
             self._remove_mark_flag(dupe)
             self.__total_count -= 1
             self.__total_size -= dupe.size
             if not group:
+                del self.__group_of_duplicate[ref]
                 self.__groups.remove(group)
                 if self.__filtered_groups:
                     self.__filtered_groups.remove(group)
diff --git a/core/tests/app_test.py b/core/tests/app_test.py
index 096db89f..1de54008 100644
--- a/core/tests/app_test.py
+++ b/core/tests/app_test.py
@@ -390,6 +390,16 @@ class TestCaseDupeGuruWithResults:
         add_fake_files_to_directories(app.directories, self.objects) # We want the scan to at least start
         app.start_scanning() # will be cancelled immediately
         eq_(len(self.rtable), 0)
+    
+    def test_selected_dupes_after_removal(self, do_setup):
+        # Purge the app's `selected_dupes` attribute when removing dupes, or else it might cause a
+        # crash later with None refs.
+        app = self.app
+        app.results.mark_all()
+        self.rtable.select([0, 1, 2, 3, 4])
+        app.remove_marked()
+        eq_(len(self.rtable), 0)
+        eq_(app.selected_dupes, [])
 
 class TestCaseDupeGuru_renameSelected:
     def pytest_funcarg__do_setup(self, request):
diff --git a/core/tests/results_test.py b/core/tests/results_test.py
index 6da07880..86383ae6 100644
--- a/core/tests/results_test.py
+++ b/core/tests/results_test.py
@@ -231,6 +231,15 @@ class TestCaseResultsWithSomeGroups:
         self.results.perform_on_marked(lambda x:None, True)
         assert not self.results.is_modified
     
+    def test_group_of_duplicate_after_removal(self):
+        # removing a duplicate also removes it from the dupe:group map.
+        dupe = self.results.groups[1].dupes[0]
+        ref = self.results.groups[1].ref
+        self.results.remove_duplicates([dupe])
+        assert self.results.get_group_of_duplicate(dupe) is None
+        # also remove group ref
+        assert self.results.get_group_of_duplicate(ref) is None
+    
 
 class TestCaseResultsWithSavedResults:
     def setup_method(self, method):