diff --git a/offlineimap/folder/LocalStatusSQLite.py b/offlineimap/folder/LocalStatusSQLite.py
index 059f741..b1246d4 100644
--- a/offlineimap/folder/LocalStatusSQLite.py
+++ b/offlineimap/folder/LocalStatusSQLite.py
@@ -41,6 +41,9 @@ class LocalStatusSQLiteFolder(BaseFolder):
 
     # Current version of our db format.
     cur_version = 2
+    # Keep track on how many threads need access to the database.
+    threads_open_count = 0
+    threads_open_lock = Lock()
 
     def __init__(self, name, repository):
         self.sep = '.' # Needs to be set before super.__init__()
@@ -62,34 +65,39 @@ class LocalStatusSQLiteFolder(BaseFolder):
         self.connection = None
 
     def openfiles(self):
-        # Try to establish connection, no need for threadsafety in __init__.
-        try:
-            self.connection = sqlite.connect(self.filename, check_same_thread=False)
-        except sqlite.OperationalError as e:
-            # Operation had failed.
-            six.reraise(UserWarning,
-                        UserWarning(
-                            "cannot open database file '%s': %s.\nYou might "
-                            "want to check the rights to that file and if it "
-                            "cleanly opens with the 'sqlite<3>' command."%
-                            (self.filename, e)),
-                        exc_info()[2])
+        # Protect the creation/upgrade of database accross threads.
+        with LocalStatusSQLiteFolder.threads_open_lock:
+            # Try to establish connection, no need for threadsafety in __init__.
 
-        # Make sure sqlite is in multithreading SERIALIZE mode.
-        assert sqlite.threadsafety == 1, 'Your sqlite is not multithreading safe.'
+            try:
+                self.connection = sqlite.connect(self.filename,
+                                                 check_same_thread=False)
+                LocalStatusSQLiteFolder.threads_open_count += 1
+            except sqlite.OperationalError as e:
+                # Operation had failed.
+                six.reraise(UserWarning,
+                            UserWarning(
+                                "cannot open database file '%s': %s.\nYou might"
+                                " want to check the rights to that file and if "
+                                "it cleanly opens with the 'sqlite<3>' command"%
+                                (self.filename, e)),
+                            exc_info()[2])
 
-        # Test if db version is current enough and if db is readable.
-        try:
-            cursor = self.connection.execute(
-                "SELECT value from metadata WHERE key='db_version'")
-        except sqlite.DatabaseError:
-            # db file missing or corrupt, recreate it.
-            self.__create_db()
-        else:
-            # Fetch db version and upgrade if needed.
-            version = int(cursor.fetchone()[0])
-            if version < LocalStatusSQLiteFolder.cur_version:
-                self.__upgrade_db(version)
+            # Make sure sqlite is in multithreading SERIALIZE mode.
+            assert sqlite.threadsafety == 1, 'Your sqlite is not multithreading safe.'
+
+            # Test if db version is current enough and if db is readable.
+            try:
+                cursor = self.connection.execute(
+                    "SELECT value from metadata WHERE key='db_version'")
+            except sqlite.DatabaseError:
+                # db file missing or corrupt, recreate it.
+                self.__create_db()
+            else:
+                # Fetch db version and upgrade if needed.
+                version = int(cursor.fetchone()[0])
+                if version < LocalStatusSQLiteFolder.cur_version:
+                    self.__upgrade_db(version)
 
     def purge(self):
         """Remove any pre-existing database."""
@@ -159,8 +167,8 @@ class LocalStatusSQLiteFolder(BaseFolder):
     def __upgrade_db(self, from_ver):
         """Upgrade the sqlite format from version 'from_ver' to current"""
 
-        if hasattr(self, 'connection'):
-            self.connection.close() #close old connections first
+        if self.connection is not None:
+            self.connection.close() # Close old connections first.
         self.connection = sqlite.connect(self.filename,
                                          check_same_thread=False)
 
@@ -185,8 +193,8 @@ class LocalStatusSQLiteFolder(BaseFolder):
 
         self.connection must point to the opened and valid SQlite
         database connection."""
-        self.ui._msg('Creating new Local Status db for %s:%s' \
-                         % (self.repository, self))
+        self.ui._msg('Creating new Local Status db for %s:%s'%
+                     (self.repository, self))
         self.connection.executescript("""
         CREATE TABLE metadata (key VARCHAR(50) PRIMARY KEY, value VARCHAR(128));
         INSERT INTO metadata VALUES('db_version', '2');
@@ -229,10 +237,13 @@ class LocalStatusSQLiteFolder(BaseFolder):
             self.messagelist[uid]['mtime'] = row[2]
 
     def closefiles(self):
-        try:
-            self.connection.close()
-        except:
-            pass
+        with LocalStatusSQLiteFolder.threads_open_lock:
+            LocalStatusSQLiteFolder.threads_open_count -= 1
+            if self.threads_open_count < 1:
+                try:
+                    self.connection.close()
+                except:
+                    pass
 
     # Interface from LocalStatusFolder
     def save(self):