--- a/browser/extensions/shield-recipe-client/test/browser.ini
+++ b/browser/extensions/shield-recipe-client/test/browser.ini
@@ -1,5 +1,6 @@
 [browser_driver_uuids.js]
 [browser_env_expressions.js]
 [browser_EventEmitter.js]
 [browser_Storage.js]
 [browser_Heartbeat.js]
+skip-if = true # bug 1325409

--- a/testing/mochitest/runtests.py
+++ b/testing/mochitest/runtests.py
@@ -819,16 +819,17 @@ class MochitestDesktop(object):
         self.countpass = 0
         self.countfail = 0
         self.counttodo = 0
 
         self.expectedError = {}
         self.result = {}
 
         self.start_script = os.path.join(here, 'start_desktop.js')
+        self.disable_leak_checking = False
 
     def update_mozinfo(self):
         """walk up directories to find mozinfo.json update the info"""
         # TODO: This should go in a more generic place, e.g. mozinfo
 
         path = SCRIPT_DIR
         dirs = set()
         while path != os.path.expanduser('~'):
@@ -1490,17 +1491,18 @@ toolbar#nav-bar {
                 dict(
                     parseKeyValue(
                         options.environment,
                         context='--setenv')))
         except KeyValueParseError as e:
             self.log.error(str(e))
             return None
 
-        browserEnv["XPCOM_MEM_BLOAT_LOG"] = self.leak_report_file
+        if not self.disable_leak_checking:
+            browserEnv["XPCOM_MEM_BLOAT_LOG"] = self.leak_report_file
 
         try:
             gmp_path = self.getGMPPluginPath(options)
             if gmp_path is not None:
                 browserEnv["MOZ_GMP_PATH"] = gmp_path
         except EnvironmentError:
             self.log.error('Could not find path to gmp-fake plugin!')
             return None
@@ -1934,22 +1936,23 @@ toolbar#nav-bar {
             cmd = os.path.abspath(app)
             args = list(extraArgs)
             args.append('-marionette')
             # TODO: mozrunner should use -foreground at least for mac
             # https://bugzilla.mozilla.org/show_bug.cgi?id=916512
             args.append('-foreground')
             self.start_script_args.append(testUrl or 'about:blank')
 
-            if detectShutdownLeaks:
+            if detectShutdownLeaks and not self.disable_leak_checking:
                 shutdownLeaks = ShutdownLeaks(self.log)
             else:
                 shutdownLeaks = None
 
-            if mozinfo.info["asan"] and (mozinfo.isLinux or mozinfo.isMac):
+            if mozinfo.info["asan"] and (mozinfo.isLinux or mozinfo.isMac) \
+                    and not self.disable_leak_checking:
                 lsanLeaks = LSANLeaks(self.log)
             else:
                 lsanLeaks = None
 
             # create an instance to process the output
             outputHandler = self.OutputHandler(
                 harness=self,
                 utilityPath=utilityPath,
@@ -2196,16 +2199,46 @@ toolbar#nav-bar {
             return self.runMochitests(options, testsToRun)
 
         # code for --run-by-dir
         dirs = self.getDirectories(options)
 
         result = 1  # default value, if no tests are run.
         for d in dirs:
             print "dir: %s" % d
+
+            # BEGIN LEAKCHECK HACK
+            # Leak checking was broken in mochitest unnoticed for a length of time. During
+            # this time, several leaks slipped through. The leak checking was fixed by bug
+            # 1325148, but it couldn't land until all the regressions were also fixed or
+            # backed out. Rather than waiting and risking new regressions, in the meantime
+            # this code will selectively disable leak checking on flavors/directories where
+            # known regressions exist. At least this way we can prevent further damage while
+            # they get fixed.
+
+            info = mozinfo.info
+            skip_leak_conditions = [
+                (options.flavor in ('browser', 'chrome', 'plain') and d.startswith('toolkit/components/extensions/test/mochitest'), 'bug 1325158'),  # noqa
+                (info['debug'] and options.flavor == 'browser' and d.startswith('browser/components/extensions/test/browser'), 'bug 1325141'),  # noqa
+                (info['debug'] and options.flavor == 'plain' and d == 'dom/animation/test/css-animations', 'bug 1325277'),  # noqa
+                (info['debug'] and options.flavor == 'plain' and d == 'dom/tests/mochitest/gamepad' and info['os'] == 'win', 'bug 1324592'),  # noqa
+                (info['debug'] and options.flavor == 'plain' and d == 'toolkit/components/prompts/test' and info['os'] == 'mac', 'bug 1325275'),  # noqa
+                (info['debug'] and options.flavor == 'plain' and d == 'tests/dom/xhr/tests', 'bug 1325438'),  # noqa
+            ]
+
+            for condition, reason in skip_leak_conditions:
+                if condition:
+                    self.log.warning('WARNING | disabling leakcheck due to {}'.format(reason))
+                    self.disable_leak_checking = True
+                    break
+            else:
+                self.disable_leak_checking = False
+
+            # END LEAKCHECK HACK
+
             tests_in_dir = [t for t in testsToRun if os.path.dirname(t) == d]
 
             # If we are using --run-by-dir, we should not use the profile path (if) provided
             # by the user, since we need to create a new directory for each run. We would face
             # problems if we use the directory provided by the user.
             result = self.runMochitests(options, tests_in_dir)
 
             # Dump the logging buffer