diff --git a/accessible/windows/msaa/Compatibility.h b/accessible/windows/msaa/Compatibility.h
index d197f0755c4..dd9a82f7cdd 100644
--- a/accessible/windows/msaa/Compatibility.h
+++ b/accessible/windows/msaa/Compatibility.h
@@ -39,26 +39,6 @@ public:
    */
   static bool IsDolphin() { return !!(sConsumers & DOLPHIN); }
 
-  /**
-   * Return true if we should disable e10s due to a detected
-   * accessibility client.
-   */
-  static bool IsBlacklistedForE10S()
-  {
-    // We currently blacklist everything except UNKNOWN and UIAUTOMATION
-    return !!(sConsumers &
-              (NVDA     |
-               JAWS     |
-               OLDJAWS  |
-               WE       |
-               DOLPHIN  |
-               SEROTEK  |
-               COBRA    |
-               ZOOMTEXT |
-               KAZAGURU |
-               YOUDAO));
-  }
-
 private:
   Compatibility();
   Compatibility(const Compatibility&);
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 9fa9b32cc63..06a2b396611 100755
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -271,6 +271,11 @@ using namespace mozilla::system;
 
 static NS_DEFINE_CID(kCClipboardCID, NS_CLIPBOARD_CID);
 
+#if defined(XP_WIN)
+// e10s forced enable pref, defined in nsAppRunner.cpp
+extern const char* kForceEnableE10sPref;
+#endif
+
 using base::ChildPrivileges;
 using base::KillProcess;
 #ifdef MOZ_ENABLE_PROFILER_SPS
@@ -1555,7 +1560,15 @@ ContentParent::Init()
     // If accessibility is running in chrome process then start it in content
     // process.
     if (nsIPresShell::IsAccessibilityActive()) {
+#if !defined(XP_WIN)
         Unused << SendActivateA11y();
+#else
+        // On Windows we currently only enable a11y in the content process
+        // for testing purposes.
+        if (Preferences::GetBool(kForceEnableE10sPref, false)) {
+            Unused << SendActivateA11y();
+        }
+#endif
     }
 #endif
 
@@ -3334,7 +3347,15 @@ ContentParent::Observe(nsISupports* aSubject,
     // gets initiated in chrome process.
     else if (aData && (*aData == '1') &&
              !strcmp(aTopic, "a11y-init-or-shutdown")) {
+#if !defined(XP_WIN)
         Unused << SendActivateA11y();
+#else
+        // On Windows we currently only enable a11y in the content process
+        // for testing purposes.
+        if (Preferences::GetBool(kForceEnableE10sPref, false)) {
+            Unused << SendActivateA11y();
+        }
+#endif
     }
 #endif
     else if (!strcmp(aTopic, "app-theme-changed")) {
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index a7d8d06bf37..3f80bd54334 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -1023,24 +1023,6 @@ nsXULAppInfo::GetAccessibilityEnabled(bool* aResult)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsXULAppInfo::GetAccessibilityIsBlacklistedForE10S(bool* aResult)
-{
-  *aResult = false;
-#if defined(ACCESSIBILITY)
-#if defined(XP_WIN)
-  if (GetAccService() && mozilla::a11y::Compatibility::IsBlacklistedForE10S()) {
-    *aResult = true;
-  }
-#elif defined(XP_MACOSX)
-  if (GetAccService()) {
-    *aResult = true;
-  }
-#endif
-#endif // defined(ACCESSIBILITY)
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsXULAppInfo::GetIs64Bit(bool* aResult)
 {
diff --git a/xpcom/system/nsIXULRuntime.idl b/xpcom/system/nsIXULRuntime.idl
index 4d7ac635d85..3823d42d2ad 100644
--- a/xpcom/system/nsIXULRuntime.idl
+++ b/xpcom/system/nsIXULRuntime.idl
@@ -23,7 +23,7 @@ bool BrowserTabsRemoteAutostart();
  *                    stable/frozen, please contact Benjamin Smedberg.
  */
 
-[scriptable, uuid(ce9d05f4-0c20-4f52-87e1-3a425e61e2f3)]
+[scriptable, uuid(a1b2e167-b748-42bf-ba85-996ec39062b9)]
 interface nsIXULRuntime : nsISupports
 {
   /**
@@ -96,12 +96,6 @@ interface nsIXULRuntime : nsISupports
    */
   readonly attribute boolean accessibilityEnabled;
 
-  /**
-   * Indicates if the active accessibility client is blacklisted for e10s.
-   * DO NOT USE! This is temporary and will be removed.
-   */
-  readonly attribute boolean accessibilityIsBlacklistedForE10S;
-
   /**
    * Indicates whether the current Firefox build is 64-bit.
    */