diff --git a/anki/collection.py b/anki/collection.py
index 774d3c26f..9da119e4d 100644
--- a/anki/collection.py
+++ b/anki/collection.py
@@ -198,7 +198,9 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?, conf=?""",
         tbls = "notes", "cards", "revlog", "graves"
         for t in tbls:
             self.db.execute("update %s set usn=0 where usn=-1" % t)
-        self._usn = 0
+        self.models.beforeUpload()
+        self.tags.beforeUpload()
+        self.decks.beforeUpload()
         self.modSchema()
         self.ls = self.scm
         self.close()
diff --git a/anki/decks.py b/anki/decks.py
index f846e3b78..4e13b3a49 100644
--- a/anki/decks.py
+++ b/anki/decks.py
@@ -266,10 +266,10 @@ class DeckManager(object):
             "update cards set did=?,usn=?,mod=? where id in "+
             ids2str(cids), did, self.col.usn(), intTime())
 
-
     def maybeAddToActive(self):
-        # since order is important, we can't just append to the end
-        self.select(self.selected())
+        # reselect current deck, or default if current has disappeared
+        c = self.current()
+        self.select(c['id'])
 
     def sendHome(self, cids):
         self.col.db.execute("""
@@ -334,3 +334,13 @@ usn=?,mod=? where id in %s""" % ids2str(cids),
         "The top level did for NAME."
         path = name.split("::")
         return self.id(path[0])
+
+    # Sync handling
+    ##########################################################################
+
+    def beforeUpload(self):
+        for d in self.all():
+            d['usn'] = 0
+        for c in self.allConf():
+            c['usn'] = 0
+        self.save()
diff --git a/anki/models.py b/anki/models.py
index c94b13f40..c8390db58 100644
--- a/anki/models.py
+++ b/anki/models.py
@@ -483,3 +483,11 @@ select id from notes where mid = ?)""" % " ".join(map),
             if ok:
                 avail.append(ord)
         return avail
+
+    # Sync handling
+    ##########################################################################
+
+    def beforeUpload(self):
+        for m in self.all():
+            m['usn'] = 0
+        self.save()
diff --git a/anki/sync.py b/anki/sync.py
index fdf14fcaf..3eabe80a5 100644
--- a/anki/sync.py
+++ b/anki/sync.py
@@ -80,7 +80,9 @@ class Syncer(object):
         runHook("sync", "sanity")
         c = self.sanityCheck()
         s = self.server.sanityCheck()
-        assert c == s
+        if c != s:
+            raise Exception("""\
+Sanity check failed. Please copy and paste the text below:\n%s\n%s""" % (c, s))
         # finalize
         runHook("sync", "finalize")
         mod = self.server.finish()
@@ -192,8 +194,7 @@ from notes where %s""" % d)
 
     def chunk(self):
         buf = dict(done=False)
-        # gather up to 5000 records
-        lim = 5000
+        lim = 2500
         while self.tablesLeft and lim:
             curTable = self.tablesLeft[0]
             if not self.cursor:
@@ -249,11 +250,16 @@ from notes where %s""" % d)
         return dict(cards=cards, notes=notes, decks=decks)
 
     def mergeGraves(self, graves):
+        # make sure the deletions don't get a usn of -1k
+        server = self.col.server
+        self.col.server = True
         # notes first, so we don't end up with duplicate graves
         self.col._remNotes(graves['notes'])
+        # then cards and decks
         self.col.remCards(graves['cards'])
         for oid in graves['decks']:
             self.col.decks.rem(oid)
+        self.col.server = server
 
     # Models
     ##########################################################################
diff --git a/anki/tags.py b/anki/tags.py
index 148079f4c..86430e9cb 100644
--- a/anki/tags.py
+++ b/anki/tags.py
@@ -177,3 +177,11 @@ class TagManager(object):
         self.col.db.execute(
             "update cards set did=?,mod=?,usn=? where nid in "+ids2str(nids),
             did, intTime(), self.col.usn())
+
+    # Sync handling
+    ##########################################################################
+
+    def beforeUpload(self):
+        for k in self.tags.keys():
+            self.tags[k] = 0
+        self.save()