diff --git a/pykolab/imap/__init__.py b/pykolab/imap/__init__.py
--- a/pykolab/imap/__init__.py
+++ b/pykolab/imap/__init__.py
@@ -408,7 +408,7 @@
 
             current_acls = self.imap.lam(self.folder_utf7(folder))
             for current_acl in current_acls.keys():
-                if current_acl == identifier:
+                if current_acl == identifier.lower():
                     _acl = current_acls[current_acl]
                     break
 
@@ -418,12 +418,17 @@
             acl = ''.join(list(set(_acl)))
 
         try:
-            self.imap.sam(self.folder_utf7(folder), identifier, acl)
+            _folder = self.folder_utf7(folder)
+            log.debug(
+                 _("IMAP SAM command with calculated ACL rights %s for %s on folder %s") % \
+                 (acl, identifier, _folder), level=8
+            )
+            self.imap.sam(_folder, identifier, acl)
         except Exception as errmsg:
             log.error(
                 _("Could not set ACL for %s on folder %s: %r") % (
                     identifier,
-                    folder,
+                    _folder,
                     errmsg
                 )
             )
@@ -892,9 +897,11 @@
         if update is True and isinstance(acls, list) and len(acls) == 0:
             acls = self.list_acls(folder)
             for subject in acls:
+		subject = subject.lower()
                 log.debug(
-                        _("Removing ACL rights %s for subject %s on folder " + \
-                            "%s") % (acls[subject], subject, folder), level=8)
+                        _("Special case: Update with ACLs %s " + \
+                          "for subject %s on folder %s") % \
+                          (acls[subject], subject, folder), level=6)
                 self.set_acl(folder, subject, '')
 
             return
@@ -906,7 +913,7 @@
 
         for acl in acls:
             exec("acl = %s" % (acl))
-            subject = acl[0]
+            subject = acl[0].lower()
             rights = acl[1]
             if len(acl) == 3:
                 epoch = acl[2]
@@ -917,8 +924,9 @@
             if update is True:
                 if old_acls is None:
                     old_acls = self.list_acls(folder)
-                    for old_subject in old_acls:
-                        old_acls[old_subject] = old_acls[old_subject]
+                    # Removing, does not make sense
+                    # for old_subject in old_acls:
+                    #    old_acls[old_subject] = old_acls[old_subject]
 
                 if subject in old_acls:
                     old_acls[subject] = None
@@ -926,7 +934,7 @@
             if epoch > (int)(time.time()):
                 log.debug(
                         _("Setting ACL rights %s for subject %s on folder " + \
-                            "%s") % (rights, subject, folder), level=8)
+                            "%s") % (rights, subject, folder), level=6)
 
                 self.set_acl(
                         folder,
@@ -936,8 +944,8 @@
 
             else:
                 log.debug(
-                        _("Removing ACL rights %s for subject %s on folder " + \
-                            "%s") % (rights, subject, folder), level=8)
+                        _("Removing %s ACL rights for subject %s on folder " + \
+                            "%s") % (rights, subject, folder), level=6)
 
                 self.set_acl(
                         folder,
@@ -950,8 +958,8 @@
             for subject in old_acls:
                 if old_acls[subject] is not None:
                     log.debug(
-                        _("Removing ACL rights %s for subject %s on folder " + \
-                            "%s") % (old_acls[subject], subject, folder), level=8)
+                        _("Update mode: Unset %s ACLs for subject %s on folder " + \
+                            "%s") % (old_acls[subject], subject, folder), level=6)
                     self.set_acl(folder, subject, '')
 
         pass