--- a/accessible/windows/msaa/MsaaAccessible.cpp
+++ b/accessible/windows/msaa/MsaaAccessible.cpp
@@ -922,16 +922,19 @@ MsaaAccessible::get_accName(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->get_accName(kVarChildIdSelf, pszName);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   nsAutoString name;
   LocalAcc()->Name(name);
 
   // The name was not provided, e.g. no alt attribute for an image. A screen
   // reader may choose to invent its own accessible name, e.g. from an image src
   // attribute. Refer to eNoNameOnPurpose return value.
   if (name.IsVoid()) return S_FALSE;
@@ -953,16 +956,19 @@ MsaaAccessible::get_accValue(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->get_accValue(kVarChildIdSelf, pszValue);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   nsAutoString value;
   LocalAcc()->Value(value);
 
   // See bug 438784: need to expose URL on doc's value attribute. For this,
   // reverting part of fix for bug 425693 to make this MSAA method behave
   // IAccessible2-style.
   if (value.IsEmpty()) return S_FALSE;
@@ -983,16 +989,19 @@ MsaaAccessible::get_accDescription(VARIA
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->get_accDescription(kVarChildIdSelf, pszDescription);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   nsAutoString description;
   LocalAcc()->Description(description);
 
   *pszDescription =
       ::SysAllocStringLen(description.get(), description.Length());
   return *pszDescription ? S_OK : E_OUTOFMEMORY;
 }
@@ -1113,16 +1122,19 @@ MsaaAccessible::get_accState(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->get_accState(kVarChildIdSelf, pvarState);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   // MSAA only has 31 states and the lowest 31 bits of our state bit mask
   // are the same states as MSAA.
   // Note: we map the following Gecko states to different MSAA states:
   //   REQUIRED -> ALERT_LOW
   //   ALERT -> ALERT_MEDIUM
   //   INVALID -> ALERT_HIGH
   //   CHECKABLE -> MARQUEED
@@ -1171,16 +1183,19 @@ MsaaAccessible::get_accKeyboardShortcut(
   }
 
   if (accessible) {
     return accessible->get_accKeyboardShortcut(kVarChildIdSelf,
                                                pszKeyboardShortcut);
   }
 
   LocalAccessible* localAcc = LocalAcc();
+  if (!localAcc) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
   KeyBinding keyBinding = localAcc->AccessKey();
   if (keyBinding.IsEmpty()) keyBinding = localAcc->KeyboardShortcut();
 
   nsAutoString shortcut;
   keyBinding.ToString(shortcut);
 
   *pszKeyboardShortcut = ::SysAllocStringLen(shortcut.get(), shortcut.Length());
   return *pszKeyboardShortcut ? S_OK : E_OUTOFMEMORY;
@@ -1196,18 +1211,23 @@ MsaaAccessible::get_accFocus(
   // clang-format off
   // VT_EMPTY:    None. This object does not have the keyboard focus itself
   //              and does not contain a child that has the keyboard focus.
   // VT_I4:       lVal is CHILDID_SELF. The object itself has the keyboard focus.
   // VT_I4:       lVal contains the child ID of the child element with the keyboard focus.
   // VT_DISPATCH: pdispVal member is the address of the IDispatch interface
   //              for the child object with the keyboard focus.
   // clang-format on
+  if (!mAcc) {
+    return CO_E_OBJNOTCONNECTED;
+  }
   LocalAccessible* localAcc = LocalAcc();
-  if (!localAcc) return CO_E_OBJNOTCONNECTED;
+  if (!localAcc) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   // Return the current IAccessible child that has focus
   LocalAccessible* focusedAccessible = localAcc->FocusedChild();
 
   if (focusedAccessible == localAcc) {
     pvarChild->vt = VT_I4;
     pvarChild->lVal = CHILDID_SELF;
   } else if (focusedAccessible) {
@@ -1328,18 +1348,23 @@ AccessibleEnumerator::Skip(unsigned long
  */
 STDMETHODIMP
 MsaaAccessible::get_accSelection(VARIANT __RPC_FAR* pvarChildren) {
   if (!pvarChildren) return E_INVALIDARG;
 
   VariantInit(pvarChildren);
   pvarChildren->vt = VT_EMPTY;
 
+  if (!mAcc) {
+    return CO_E_OBJNOTCONNECTED;
+  }
   LocalAccessible* localAcc = LocalAcc();
-  if (!localAcc) return CO_E_OBJNOTCONNECTED;
+  if (!localAcc) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   if (!localAcc->IsSelect()) {
     return S_OK;
   }
 
   AutoTArray<LocalAccessible*, 10> selectedItems;
   localAcc->SelectedItems(&selectedItems);
   uint32_t count = selectedItems.Length();
@@ -1371,16 +1396,19 @@ MsaaAccessible::get_accDefaultAction(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->get_accDefaultAction(kVarChildIdSelf, pszDefaultAction);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   nsAutoString defaultAction;
   LocalAcc()->ActionNameAt(0, defaultAction);
 
   *pszDefaultAction =
       ::SysAllocStringLen(defaultAction.get(), defaultAction.Length());
   return *pszDefaultAction ? S_OK : E_OUTOFMEMORY;
 }
@@ -1393,16 +1421,19 @@ MsaaAccessible::accSelect(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->accSelect(flagsSelect, kVarChildIdSelf);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   LocalAccessible* localAcc = LocalAcc();
   if (flagsSelect & SELFLAG_TAKEFOCUS) {
     if (XRE_IsContentProcess()) {
       // In this case we might have been invoked while the IPC MessageChannel is
       // waiting on a sync reply. We cannot dispatch additional IPC while that
       // is happening, so we dispatch TakeFocus from the main thread to
       // guarantee that we are outside any IPC.
@@ -1455,17 +1486,17 @@ MsaaAccessible::accLocation(
 
   if (accessible) {
     return accessible->accLocation(pxLeft, pyTop, pcxWidth, pcyHeight,
                                    kVarChildIdSelf);
   }
 
   LocalAccessible* localAcc = LocalAcc();
   if (!localAcc) {
-    return CO_E_OBJNOTCONNECTED;
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
   }
 
   nsIntRect rect = localAcc->Bounds();
 
   *pxLeft = rect.X();
   *pyTop = rect.Y();
   *pcxWidth = rect.Width();
   *pcyHeight = rect.Height();
@@ -1567,18 +1598,23 @@ STDMETHODIMP
 MsaaAccessible::accHitTest(
     /* [in] */ long xLeft,
     /* [in] */ long yTop,
     /* [retval][out] */ VARIANT __RPC_FAR* pvarChild) {
   if (!pvarChild) return E_INVALIDARG;
 
   VariantInit(pvarChild);
 
+  if (!mAcc) {
+    return CO_E_OBJNOTCONNECTED;
+  }
   LocalAccessible* localAcc = LocalAcc();
-  if (!localAcc) return CO_E_OBJNOTCONNECTED;
+  if (!localAcc) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   LocalAccessible* accessible = localAcc->LocalChildAtPoint(
       xLeft, yTop, Accessible::EWhichChildAtPoint::DirectChild);
 
   // if we got a child
   if (accessible) {
     // if the child is us
     if (accessible == localAcc) {
@@ -1603,16 +1639,19 @@ MsaaAccessible::accDoDefaultAction(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->accDoDefaultAction(kVarChildIdSelf);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   return LocalAcc()->DoAction(0) ? S_OK : E_INVALIDARG;
 }
 
 STDMETHODIMP
 MsaaAccessible::put_accName(
     /* [optional][in] */ VARIANT varChild,
     /* [in] */ BSTR szName) {
@@ -1627,16 +1666,19 @@ MsaaAccessible::put_accValue(
   HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
   if (FAILED(hr)) {
     return hr;
   }
 
   if (accessible) {
     return accessible->put_accValue(kVarChildIdSelf, szValue);
   }
+  if (mAcc->IsRemote()) {
+    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
+  }
 
   HyperTextAccessible* ht = LocalAcc()->AsHyperText();
   if (!ht) {
     return E_NOTIMPL;
   }
 
   uint32_t length = ::SysStringLen(szValue);
   nsAutoString text(szValue, length);

--- a/accessible/windows/msaa/MsaaRootAccessible.cpp
+++ b/accessible/windows/msaa/MsaaRootAccessible.cpp
@@ -121,16 +121,19 @@ MsaaRootAccessible::get_accFocus(
     // remote document because this causes mysterious intermittent crashes
     // when we're called by UIA clients; see bug 1424505.
     return hr;
   }
 
   // The base implementation reported no focus.
   // Focus might be in a remote document.
   // (The base implementation can't handle this.)
+  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
+    return S_FALSE;
+  }
   // Get the document in the active tab.
   RootAccessible* rootAcc = RootAcc();
   if (!rootAcc) {
     return CO_E_OBJNOTCONNECTED;
   }
   RemoteAccessible* docProxy = rootAcc->GetPrimaryRemoteTopLevelContentDoc();
   if (!docProxy) {
     return hr;