diff --git a/anki/collection.py b/anki/collection.py
index d54cdf932..a6abe04b6 100644
--- a/anki/collection.py
+++ b/anki/collection.py
@@ -171,7 +171,7 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?, conf=?""",
         self.load()
         self.lock()
 
-    def modSchema(self, check=True):
+    def modSchema(self, check):
         "Mark schema modified. Call this first so user can abort if necessary."
         if not self.schemaChanged():
             if check and not runFilter("modSchema", True):
@@ -197,7 +197,7 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?, conf=?""",
         self.models.beforeUpload()
         self.tags.beforeUpload()
         self.decks.beforeUpload()
-        self.modSchema()
+        self.modSchema(check=False)
         self.ls = self.scm
         # ensure db is compacted before upload
         self.db.execute("vacuum")
diff --git a/anki/decks.py b/anki/decks.py
index b939bd5e8..a09194fab 100644
--- a/anki/decks.py
+++ b/anki/decks.py
@@ -344,7 +344,7 @@ class DeckManager(object):
     def remConf(self, id):
         "Remove a configuration and update all decks using it."
         assert int(id) != 1
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         del self.dconf[str(id)]
         for g in self.all():
             # ignore cram decks
diff --git a/anki/models.py b/anki/models.py
index 7f46b524b..bd363514b 100644
--- a/anki/models.py
+++ b/anki/models.py
@@ -147,7 +147,7 @@ class ModelManager(object):
 
     def rem(self, m):
         "Delete model, and all its cards/notes."
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         current = self.current()['id'] == m['id']
         # delete notes/cards
         self.col.remCards(self.col.db.list("""
@@ -241,7 +241,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
 
     def setSortIdx(self, m, idx):
         assert idx >= 0 and idx < len(m['flds'])
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         m['sortf'] = idx
         self.col.updateFieldCache(self.nids(m))
         self.save(m)
@@ -249,7 +249,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
     def addField(self, m, field):
         # only mod schema if model isn't new
         if m['id']:
-            self.col.modSchema()
+            self.col.modSchema(check=True)
         m['flds'].append(field)
         self._updateFieldOrds(m)
         self.save(m)
@@ -259,7 +259,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
         self._transformFields(m, add)
 
     def remField(self, m, field):
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         # save old sort field
         sortFldName = m['flds'][m['sortf']]['name']
         idx = m['flds'].index(field)
@@ -282,7 +282,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
         self.renameField(m, field, None)
 
     def moveField(self, m, field, idx):
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         oldidx = m['flds'].index(field)
         if oldidx == idx:
             return
@@ -303,7 +303,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
         self._transformFields(m, move)
 
     def renameField(self, m, field, newName):
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         pat = r'{{(.*)([:#^/]|[^:#/^}][^:}]*?:|)%s}}'
         def wrap(txt):
             def repl(match):
@@ -347,7 +347,7 @@ and notes.mid = ? and cards.ord = ?""", m['id'], ord)
     def addTemplate(self, m, template):
         "Note: should col.genCards() afterwards."
         if m['id']:
-            self.col.modSchema()
+            self.col.modSchema(check=True)
         m['tmpls'].append(template)
         self._updateTemplOrds(m)
         self.save(m)
@@ -370,7 +370,7 @@ having count() < 2
 limit 1""" % ids2str(cids)):
             return False
         # ok to proceed; remove cards
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         self.col.remCards(cids)
         # shift ordinals
         self.col.db.execute("""
@@ -414,7 +414,7 @@ select id from notes where mid = ?)""" % " ".join(map),
     # - newModel should be self if model is not changing
 
     def change(self, m, nids, newModel, fmap, cmap):
-        self.col.modSchema()
+        self.col.modSchema(check=True)
         assert newModel['id'] == m['id'] or (fmap and cmap)
         if fmap:
             self._changeNotes(nids, newModel, fmap)
diff --git a/anki/storage.py b/anki/storage.py
index d83fef1ca..e209c51ff 100644
--- a/anki/storage.py
+++ b/anki/storage.py
@@ -88,7 +88,7 @@ def _upgrade(col, ver):
             d['collapsed'] = False
             col.decks.save(d)
     if ver < 4:
-        col.modSchema()
+        col.modSchema(check=False)
         clozes = []
         for m in col.models.all():
             if not "{{cloze:" in m['tmpls'][0]['qfmt']:
@@ -103,7 +103,7 @@ def _upgrade(col, ver):
         col.db.execute("update cards set odue = 0 where queue = 2")
         col.db.execute("update col set ver = 5")
     if ver < 6:
-        col.modSchema()
+        col.modSchema(check=False)
         import anki.models
         for m in col.models.all():
             m['css'] = anki.models.defaultModel['css']
@@ -117,13 +117,13 @@ def _upgrade(col, ver):
             col.models.save(m)
         col.db.execute("update col set ver = 6")
     if ver < 7:
-        col.modSchema()
+        col.modSchema(check=False)
         col.db.execute(
             "update cards set odue = 0 where (type = 1 or queue = 2) "
             "and not odid")
         col.db.execute("update col set ver = 7")
     if ver < 8:
-        col.modSchema()
+        col.modSchema(check=False)
         col.db.execute(
             "update cards set due = due / 1000 where due > 4294967296")
         col.db.execute("update col set ver = 8")
@@ -149,7 +149,7 @@ def _upgrade(col, ver):
 update cards set left = left + left*1000 where queue = 1""")
         col.db.execute("update col set ver = 10")
     if ver < 11:
-        col.modSchema()
+        col.modSchema(check=False)
         for d in col.decks.all():
             if d['dyn']:
                 order = d['order']
diff --git a/anki/sync.py b/anki/sync.py
index f9464d87a..229ac4e5b 100644
--- a/anki/sync.py
+++ b/anki/sync.py
@@ -183,7 +183,7 @@ class Syncer(object):
         if ret['status'] != "ok":
             # roll back and force full sync
             self.col.rollback()
-            self.col.modSchema()
+            self.col.modSchema(False)
             self.col.save()
             return "sanityCheckFailed"
         # finalize
diff --git a/aqt/main.py b/aqt/main.py
index eff919904..246683dfe 100644
--- a/aqt/main.py
+++ b/aqt/main.py
@@ -69,7 +69,6 @@ class AnkiQt(QMainWindow):
 
     def setupUI(self):
         self.col = None
-        self.hideSchemaMsg = False
         self.setupAppMsg()
         self.setupKeys()
         self.setupThreads()
@@ -265,7 +264,6 @@ To import into a password protected profile, please open the profile before atte
     ##########################################################################
 
     def loadCollection(self):
-        self.hideSchemaMsg = True
         cpath = self.pm.collectionPath()
         try:
             self.col = Collection(cpath, log=True)
@@ -287,7 +285,6 @@ Debug info:
                 return
             self.unloadProfile()
             raise
-        self.hideSchemaMsg = False
         self.progress.setupDB(self.col.db)
         self.maybeEnableUndo()
         self.moveToState("deckBrowser")
@@ -903,12 +900,6 @@ and if the problem comes up again, please ask on the support site."""))
     ##########################################################################
 
     def onSchemaMod(self, arg):
-        # if triggered in sync, make sure we don't use the gui
-        if not self.inMainThread():
-            return True
-        # if from the full sync menu, ignore
-        if self.hideSchemaMsg:
-            return True
         return askUser(_("""\
 The requested change will require a full upload of the database when \
 you next synchronize your collection. If you have reviews or other changes \
diff --git a/aqt/preferences.py b/aqt/preferences.py
index da9185cd4..37453d9b1 100644
--- a/aqt/preferences.py
+++ b/aqt/preferences.py
@@ -105,10 +105,8 @@ Not currently enabled; click the sync button in the main window to enable."""))
         self.prof['autoSync'] = self.form.syncOnProgramOpen.isChecked()
         self.prof['syncMedia'] = self.form.syncMedia.isChecked()
         if self.form.fullSync.isChecked():
-            self.mw.hideSchemaMsg = True
-            self.mw.col.modSchema()
+            self.mw.col.modSchema(check=False)
             self.mw.col.setMod()
-            self.mw.hideSchemaMsg = False
 
     # Backup
     ######################################################################