diff --git a/toolkit/crashreporter/test/unit/test_crashreporter_crash.js b/toolkit/crashreporter/test/unit/test_crashreporter_crash.js
index f3d51d81f70..70e432d6d5f 100644
--- a/toolkit/crashreporter/test/unit/test_crashreporter_crash.js
+++ b/toolkit/crashreporter/test/unit/test_crashreporter_crash.js
@@ -1,11 +1,5 @@
 function run_test()
 {
-  var isOSX = ("nsILocalFileMac" in Components.interfaces);
-  if (isOSX) {
-    dump("INFO | test_crashreporter.js | Skipping test on mac, bug 599475")
-    return;
-  }
-
   if (!("@mozilla.org/toolkit/crash-reporter;1" in Components.classes)) {
     dump("INFO | test_crashreporter.js | Can't test crashreporter in a non-libxul build.\n");
     return;
diff --git a/toolkit/crashreporter/test/unit/test_crashreporter_crash_profile_lock.js b/toolkit/crashreporter/test/unit/test_crashreporter_crash_profile_lock.js
index 6b9616ada4f..877c6b0485a 100644
--- a/toolkit/crashreporter/test/unit/test_crashreporter_crash_profile_lock.js
+++ b/toolkit/crashreporter/test/unit/test_crashreporter_crash_profile_lock.js
@@ -1,11 +1,5 @@
 function run_test()
 {
-  var isOSX = ("nsILocalFileMac" in Components.interfaces);
-  if (isOSX) {
-    dump("INFO | test_crashreporter_crash_profile_lock.js | Skipping test on mac, bug 599475")
-    return;
-  }
-
   if (!("@mozilla.org/toolkit/crash-reporter;1" in Components.classes)) {
     dump("INFO | test_crashreporter.js | Can't test crashreporter in a non-libxul build.\n");
     return;
diff --git a/uriloader/exthandler/tests/unit/test_punycodeURIs.js b/uriloader/exthandler/tests/unit/test_punycodeURIs.js
index 72c8f18d712..b61e3ed8527 100644
--- a/uriloader/exthandler/tests/unit/test_punycodeURIs.js
+++ b/uriloader/exthandler/tests/unit/test_punycodeURIs.js
@@ -93,12 +93,6 @@ function checkFile() {
 }
 
 function run_test() {
-  var isOSX = ("nsILocalFileMac" in Components.interfaces);
-  if (isOSX) {
-    dump("INFO | test_punycodeURIs.js | Skipping test on mac, bug 599475")
-    return;
-  }
-
   // set up the uri to test with
   var ioService =
     Components.classes["@mozilla.org/network/io-service;1"]