diff --git a/.hgignore b/.hgignore
index 2de004e5..53c6f972 100644
--- a/.hgignore
+++ b/.hgignore
@@ -15,7 +15,8 @@ cocoa/*/build
 cocoa/*/dg_cocoa.plugin
 qt/base/*_rc.py
 qt/base/*_ui.py
-qt/se/*_ui.py
+qt/*/*_ui.py
+qt/pe/modules/block/block.c
 help_se/dupeguru_help
 help_me/dupeguru_me_help
 help_pe/dupeguru_pe_help
\ No newline at end of file
diff --git a/cocoa/pe/dg_cocoa.py b/cocoa/pe/dg_cocoa.py
index 49634f13..6d39ba92 100644
--- a/cocoa/pe/dg_cocoa.py
+++ b/cocoa/pe/dg_cocoa.py
@@ -38,7 +38,7 @@ class PyDupeGuru(PyApp):
         self.app.scanner.ignore_list.Clear()
     
     def clearPictureCache(self):
-        self.app.scanner.cached_blocks.clear()
+        self.app.scanner.clear_picture_cache()
     
     def doScan(self):
         return self.app.start_scanning()
diff --git a/core_pe/app_cocoa.py b/core_pe/app_cocoa.py
index 08c3525f..14febe30 100644
--- a/core_pe/app_cocoa.py
+++ b/core_pe/app_cocoa.py
@@ -136,8 +136,7 @@ class DupeGuruPE(app_cocoa.DupeGuru):
         app_cocoa.DupeGuru.__init__(self, data, 'dupeGuru Picture Edition', appid=5)
         self.scanner = ScannerPE()
         self.directories = Directories()
-        p = op.join(self.appdata, 'cached_pictures.db')
-        self.scanner.cached_blocks = Cache(p)
+        self.scanner.cache_path = op.join(self.appdata, 'cached_pictures.db')
     
     def _do_delete(self, j):
         def op(dupe):
diff --git a/core_pe/cache.py b/core_pe/cache.py
index d642b52b..d44ecccd 100644
--- a/core_pe/cache.py
+++ b/core_pe/cache.py
@@ -10,8 +10,6 @@ import os
 import logging
 import sqlite3 as sqlite
 
-import hsutil.sqlite
-
 from _cache import string_to_colors
 
 def colors_to_string(colors):
@@ -35,31 +33,10 @@ def colors_to_string(colors):
 class Cache(object):
     """A class to cache picture blocks.
     """
-    def __init__(self, db=':memory:', threaded=True):
-        def create_tables():
-            sql = "create table pictures(path TEXT, blocks TEXT)"
-            self.con.execute(sql);
-            sql = "create index idx_path on pictures (path)"
-            self.con.execute(sql)
-        
+    def __init__(self, db=':memory:'):
         self.dbname = db
-        if threaded:
-            self.con = hsutil.sqlite.ThreadedConn(db, True)
-        else:
-            self.con = sqlite.connect(db, isolation_level=None)
-        try:
-            self.con.execute("select * from pictures where 1=2")
-        except sqlite.OperationalError: # new db
-            create_tables()
-        except sqlite.DatabaseError, e: # corrupted db
-            logging.warning('Could not create picture cache because of an error: %s', str(e))
-            self.con.close()
-            os.remove(db)
-            if threaded:
-                self.con = hsutil.sqlite.ThreadedConn(db, True)
-            else:
-                self.con = sqlite.connect(db, isolation_level=None)
-            create_tables()
+        self.con = None
+        self._create_con()
     
     def __contains__(self, key):
         sql = "select count(*) from pictures where path = ?"
@@ -108,9 +85,36 @@ class Cache(object):
         except sqlite.DatabaseError, e:
             logging.warning('DatabaseError while setting %r for key %r: %s', value, key, str(e))
     
+    def _create_con(self, second_try=False):
+        def create_tables():
+            sql = "create table pictures(path TEXT, blocks TEXT)"
+            self.con.execute(sql);
+            sql = "create index idx_path on pictures (path)"
+            self.con.execute(sql)
+        
+        self.con = sqlite.connect(self.dbname, isolation_level=None)
+        try:
+            self.con.execute("select * from pictures where 1=2")
+        except sqlite.OperationalError: # new db
+            create_tables()
+        except sqlite.DatabaseError, e: # corrupted db
+            if second_try:
+                raise # Something really strange is happening
+            logging.warning('Could not create picture cache because of an error: %s', str(e))
+            self.con.close()
+            os.remove(self.dbname)
+            self._create_con(second_try=True)
+    
     def clear(self):
-        sql = "delete from pictures"
-        self.con.execute(sql)
+        self.close()
+        if self.dbname != ':memory:':
+            os.remove(self.dbname)
+        self._create_con()
+    
+    def close(self):
+        if self.con is not None:
+            self.con.close()
+        self.con = None
     
     def filter(self, func):
         to_delete = [key for key in self if not func(key)]
diff --git a/core_pe/matchbase.py b/core_pe/matchbase.py
index 678455e8..a988e2bb 100644
--- a/core_pe/matchbase.py
+++ b/core_pe/matchbase.py
@@ -26,20 +26,21 @@ BLOCK_COUNT_PER_SIDE = 15
 # collection made by the main process.
 RESULTS_QUEUE_LIMIT = multiprocessing.cpu_count() * 2
 
-def prepare_pictures(pictures, cached_blocks, j=job.nulljob):
+def prepare_pictures(pictures, cache_path, j=job.nulljob):
     # The MemoryError handlers in there use logging without first caring about whether or not
     # there is enough memory left to carry on the operation because it is assumed that the
     # MemoryError happens when trying to read an image file, which is freed from memory by the
     # time that MemoryError is raised.
+    cache = Cache(cache_path)
     prepared = [] # only pictures for which there was no error getting blocks
     try:
         for picture in j.iter_with_progress(pictures, 'Analyzed %d/%d pictures'):
             picture.dimensions
             picture.unicode_path = unicode(picture.path)
             try:
-                if picture.unicode_path not in cached_blocks:
+                if picture.unicode_path not in cache:
                     blocks = picture.get_blocks(BLOCK_COUNT_PER_SIDE)
-                    cached_blocks[picture.unicode_path] = blocks
+                    cache[picture.unicode_path] = blocks
                 prepared.append(picture)
             except IOError as e:
                 logging.warning(unicode(e))
@@ -49,6 +50,7 @@ def prepare_pictures(pictures, cached_blocks, j=job.nulljob):
                     raise
     except MemoryError:
         logging.warning('Ran out of memory while preparing pictures')
+    cache.close()
     return prepared
 
 def get_match(first, second, percentage):
@@ -57,7 +59,7 @@ def get_match(first, second, percentage):
     return Match(first, second, percentage)
 
 def async_compare(ref_id, other_ids, dbname, threshold):
-    cache = Cache(dbname, threaded=False)
+    cache = Cache(dbname)
     limit = 100 - threshold
     ref_blocks = cache[ref_id]
     pairs = cache.get_multiple(other_ids)
@@ -70,10 +72,10 @@ def async_compare(ref_id, other_ids, dbname, threshold):
             percentage = 0
         if percentage >= threshold:
             results.append((ref_id, other_id, percentage))
-    cache.con.close()
+    cache.close()
     return results
     
-def getmatches(pictures, cached_blocks, threshold=75, match_scaled=False, j=job.nulljob):
+def getmatches(pictures, cache_path, threshold=75, match_scaled=False, j=job.nulljob):
     def empty_out_queue(queue, into):
         try:
             while True:
@@ -82,9 +84,9 @@ def getmatches(pictures, cached_blocks, threshold=75, match_scaled=False, j=job.
             pass
     
     j = j.start_subjob([3, 7])
-    pictures = prepare_pictures(pictures, cached_blocks, j)
+    pictures = prepare_pictures(pictures, cache_path, j)
     j = j.start_subjob([9, 1], 'Preparing for matching')
-    cache = cached_blocks
+    cache = Cache(cache_path)
     id2picture = {}
     dimensions2pictures = defaultdict(set)
     for picture in pictures:
@@ -95,6 +97,7 @@ def getmatches(pictures, cached_blocks, threshold=75, match_scaled=False, j=job.
                 dimensions2pictures[picture.dimensions].add(picture)
         except ValueError:
             pass
+    cache.close()
     pictures = [p for p in pictures if hasattr(p, 'cache_id')]
     pool = multiprocessing.Pool()
     async_results = []
@@ -108,7 +111,7 @@ def getmatches(pictures, cached_blocks, threshold=75, match_scaled=False, j=job.
             others = [pic for pic in others if not pic.is_ref]
         if others:
             cache_ids = [f.cache_id for f in others]
-            args = (ref.cache_id, cache_ids, cached_blocks.dbname, threshold)
+            args = (ref.cache_id, cache_ids, cache_path, threshold)
             async_results.append(pool.apply_async(async_compare, args))
         if len(async_results) > RESULTS_QUEUE_LIMIT:
             result = async_results.pop(0)
diff --git a/core_pe/scanner.py b/core_pe/scanner.py
index cf57a5f4..1234fa85 100644
--- a/core_pe/scanner.py
+++ b/core_pe/scanner.py
@@ -10,12 +10,18 @@
 from core.scanner import Scanner
 
 from . import matchbase
+from .cache import Cache
 
 class ScannerPE(Scanner):
-    cached_blocks = None
+    cache_path = None
     match_scaled = False
     threshold = 75
     
     def _getmatches(self, files, j):
-        return matchbase.getmatches(files, self.cached_blocks, self.threshold, self.match_scaled, j)
+        return matchbase.getmatches(files, self.cache_path, self.threshold, self.match_scaled, j)
+    
+    def clear_picture_cache(self):
+        cache = Cache(self.cache_path)
+        cache.clear()
+        cache.close()
     
diff --git a/qt/pe/app.py b/qt/pe/app.py
index ceaddca2..ac2c437e 100644
--- a/qt/pe/app.py
+++ b/qt/pe/app.py
@@ -65,7 +65,7 @@ class DupeGuru(DupeGuruBase):
     def _setup(self):
         self.scanner = ScannerPE()
         self.directories.fileclasses = [File]
-        self.scanner.cached_blocks = Cache(op.join(self.appdata, 'cached_pictures.db'))
+        self.scanner.cache_path = op.join(self.appdata, 'cached_pictures.db')
         DupeGuruBase._setup(self)
     
     def _update_options(self):
diff --git a/qt/pe/main_window.py b/qt/pe/main_window.py
index c5cfe1f8..3dc3cfaa 100644
--- a/qt/pe/main_window.py
+++ b/qt/pe/main_window.py
@@ -22,6 +22,6 @@ class MainWindow(MainWindowBase):
         title = "Clear Picture Cache"
         msg = "Do you really want to remove all your cached picture analysis?"
         if self._confirm(title, msg, QMessageBox.No):
-            self.app.scanner.cached_blocks.clear()
+            self.app.scanner.clear_picture_cache()
             QMessageBox.information(self, title, "Picture cache cleared.")
     
\ No newline at end of file