diff --git a/aqt/__init__.py b/aqt/__init__.py
index 002b87d6e..3db24c6ff 100644
--- a/aqt/__init__.py
+++ b/aqt/__init__.py
@@ -55,11 +55,15 @@ class DialogManager(object):
         self._dialogs[name] = [self._dialogs[name][0], None]
 
     def closeAll(self):
+        "True if all closed successfully."
         for (n, (creator, instance)) in self._dialogs.items():
             if instance:
+                if not instance.canClose():
+                    return False
                 instance.forceClose = True
                 instance.close()
                 self.close(n)
+        return True
 
 dialogs = DialogManager()
 
diff --git a/aqt/browser.py b/aqt/browser.py
index 508f2bdf5..f8bd41768 100644
--- a/aqt/browser.py
+++ b/aqt/browser.py
@@ -441,6 +441,9 @@ class Browser(QMainWindow):
         self.mw.maybeReset()
         evt.accept()
 
+    def canClose(self):
+        return True
+
     def keyPressEvent(self, evt):
         "Show answer on RET or register answer."
         if evt.key() == Qt.Key_Escape:
diff --git a/aqt/editcurrent.py b/aqt/editcurrent.py
index 29e98f0fe..c029fc36e 100644
--- a/aqt/editcurrent.py
+++ b/aqt/editcurrent.py
@@ -64,3 +64,6 @@ class EditCurrent(QDialog):
         self.mw.moveToState("review")
         saveGeom(self, "editcurrent")
         aqt.dialogs.close("EditCurrent")
+
+    def canClose(self):
+        return True
diff --git a/aqt/main.py b/aqt/main.py
index 7f2af17a1..40b4c7add 100644
--- a/aqt/main.py
+++ b/aqt/main.py
@@ -226,9 +226,10 @@ To import into a password protected profile, please open the profile before atte
         if not self.pm.profile:
             # already unloaded
             return
-        self.state = "profileManager"
         runHook("unloadProfile")
-        self.unloadCollection()
+        if not self.unloadCollection():
+            return
+        self.state = "profileManager"
         self.onSync(auto=True, reload=False)
         self.pm.profile['mainWindowGeom'] = self.saveGeometry()
         self.pm.profile['mainWindowState'] = self.saveState()
@@ -257,14 +258,17 @@ how to restore from a backup.""")
         self.moveToState("deckBrowser")
 
     def unloadCollection(self):
+        "True if unload successful."
         if self.col:
-            self.closeAllCollectionWindows()
+            if not self.closeAllCollectionWindows():
+                return
             self.maybeOptimize()
             self.col.close()
             self.col = None
             self.progress.start(immediate=True)
             self.backup()
             self.progress.finish()
+            return True
 
     # Backup and auto-optimize
     ##########################################################################
@@ -469,7 +473,7 @@ title="%s">%s</button>''' % (
         self.form.centralwidget.setLayout(self.mainLayout)
 
     def closeAllCollectionWindows(self):
-        aqt.dialogs.closeAll()
+        return aqt.dialogs.closeAll()
 
     # Components
     ##########################################################################
@@ -521,7 +525,8 @@ title="%s">%s</button>''' % (
         if not auto or (self.pm.profile['syncKey'] and
                         self.pm.profile['autoSync']):
             from aqt.sync import SyncManager
-            self.unloadCollection()
+            if not self.unloadCollection():
+                return
             # set a sync state so the refresh timer doesn't fire while deck
             # unloaded
             self.state = "sync"