diff --git a/anki/importing/anki2.py b/anki/importing/anki2.py
index 0b41ad804..7ccd8835b 100644
--- a/anki/importing/anki2.py
+++ b/anki/importing/anki2.py
@@ -4,7 +4,7 @@
 
 import os
 from anki import Collection
-from anki.utils import intTime, splitFields, joinFields, checksum
+from anki.utils import intTime, splitFields, joinFields, checksum, guid64
 from anki.importing.base import Importer
 from anki.lang import _
 from anki.lang import ngettext
@@ -96,8 +96,24 @@ class Anki2Importer(Importer):
             # turn the db result into a mutable list
             note = list(note)
             guid, mid = note[1:3]
-            # missing from local col?
-            if guid not in self._notes:
+            duplicate = False
+            guidChange = False
+            # do we have the same guid?
+            if guid in self._notes:
+                # and do they share the same model id?
+                if self._notes[guid][2] == mid:
+                    # and do they share the same schema?
+                    srcM = self.src.models.get(mid)
+                    dstM = self.dst.models.get(self._notes[guid][2])
+                    if (self.src.models.scmhash(srcM) ==
+                        self.src.models.scmhash(dstM)):
+                        # then it's safe to treat as a duplicate
+                        duplicate = True
+                if not duplicate:
+                    # not identical models, so we need to change guid
+                    guidChange = True
+            # missing from local col or divergent model?
+            if not duplicate:
                 # get corresponding local model
                 lmid = self._mid(mid)
                 # ensure id is unique
@@ -111,11 +127,14 @@ class Anki2Importer(Importer):
                 note[6] = self._mungeMedia(mid, note[6])
                 add.append(note)
                 dirty.append(note[0])
+                # if it was originally the same as a note in this deck but the
+                # models have diverged, we need to change the guid
+                if guidChange:
+                    guid = guid64()
                 # note we have the added note
                 self._notes[guid] = (note[0], note[3], note[2])
             else:
                 dupes += 1
-                pass
                 ## update existing note - not yet tested; for post 2.0
                 # newer = note[3] > mod
                 # if self.allowUpdate and self._mid(mid) == mid and newer:
diff --git a/anki/models.py b/anki/models.py
index e6ca38c67..e4044875d 100644
--- a/anki/models.py
+++ b/anki/models.py
@@ -452,6 +452,8 @@ select id from notes where mid = ?)""" % " ".join(map),
         s = ""
         for f in m['flds']:
             s += f['name']
+        for t in m['tmpls']:
+            s += t['name']
         return fieldChecksum(s)
 
     # Required field/text cache
diff --git a/anki/upgrade.py b/anki/upgrade.py
index 259720586..4434ec541 100644
--- a/anki/upgrade.py
+++ b/anki/upgrade.py
@@ -341,11 +341,8 @@ insert or replace into col select id, cast(created as int), :t,
         mods = {}
         for row in db.all(
             "select id, name from models"):
-            while 1:
-                t = intTime(1000)
-                if t not in times:
-                    times[t] = True
-                    break
+            # use only first 31 bits
+            t = abs(row[0]) >> 32
             m = anki.models.defaultModel.copy()
             m['id'] = t
             m['name'] = row[1]
diff --git a/tests/support/diffmodels1.anki b/tests/support/diffmodels1.anki
new file mode 100644
index 000000000..aa2103b05
Binary files /dev/null and b/tests/support/diffmodels1.anki differ
diff --git a/tests/support/diffmodels2.anki b/tests/support/diffmodels2.anki
new file mode 100644
index 000000000..0f921c90a
Binary files /dev/null and b/tests/support/diffmodels2.anki differ
diff --git a/tests/test_importing.py b/tests/test_importing.py
index a40e68bb2..023996b3f 100644
--- a/tests/test_importing.py
+++ b/tests/test_importing.py
@@ -138,6 +138,26 @@ def test_anki1():
     imp.run()
     check()
 
+def test_anki1_diffmodels():
+    # create a new empty deck
+    dst = getEmptyDeck()
+    # import the 1 card version of the model
+    tmp = getUpgradeDeckPath("diffmodels1.anki")
+    imp = Anki1Importer(dst, tmp)
+    imp.run()
+    before = dst.noteCount()
+    # repeating the process should do nothing
+    imp = Anki1Importer(dst, tmp)
+    imp.run()
+    assert before == dst.noteCount()
+    # then the 2 card version
+    tmp = getUpgradeDeckPath("diffmodels2.anki")
+    imp = Anki1Importer(dst, tmp)
+    imp.run()
+    after = dst.noteCount()
+    # as the model schemas differ, should have been imported as new model
+    assert after == before + 1
+
 def test_csv():
     deck = getEmptyDeck()
     file = unicode(os.path.join(testDir, "support/text-2fields.txt"))