--- a/browser/extensions/pocket/jar.mn
+++ b/browser/extensions/pocket/jar.mn
@@ -1,10 +1,10 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 [features/firefox@getpocket.com] chrome.jar:
-% content pocket %content/ contentaccessible=yes
+% content pocket %content/
 % skin pocket-shared classic/1.0 %skin/shared/
   content/  (content/*)
   skin/shared (skin/shared/*)
 

--- a/xpcom/io/nsLocalFileCommon.cpp
+++ b/xpcom/io/nsLocalFileCommon.cpp
@@ -56,21 +56,29 @@ nsLocalFile::CreateUnique(uint32_t aType
 #else
   nsAutoCString pathName, leafName, rootName, suffix;
   rv = GetNativePath(pathName);
 #endif
   if (NS_FAILED(rv)) {
     return rv;
   }
 
+  auto FailedBecauseExists = [&] (nsresult aRv) {
+    if (aRv == NS_ERROR_FILE_ACCESS_DENIED) {
+      bool exists;
+      return NS_SUCCEEDED(Exists(&exists)) && exists;
+    }
+    return aRv == NS_ERROR_FILE_ALREADY_EXISTS;
+  };
+
   longName = (pathName.Length() + kMaxSequenceNumberLength >
               kMaxFilenameLength);
   if (!longName) {
     rv = Create(aType, aAttributes);
-    if (rv != NS_ERROR_FILE_ALREADY_EXISTS) {
+    if (!FailedBecauseExists(rv)) {
       return rv;
     }
   }
 
 #ifdef XP_WIN
   rv = GetLeafName(leafName);
   if (NS_FAILED(rv)) {
     return rv;
@@ -123,32 +131,32 @@ nsLocalFile::CreateUnique(uint32_t aType
         return NS_ERROR_FILE_UNRECOGNIZED_PATH;
       }
     }
 
     rootName.SetLength(maxRootLength);
     SetNativeLeafName(rootName + suffix);
 #endif
     nsresult rvCreate = Create(aType, aAttributes);
-    if (rvCreate != NS_ERROR_FILE_ALREADY_EXISTS) {
+    if (!FailedBecauseExists(rvCreate)) {
       return rvCreate;
     }
   }
 
   for (int indx = 1; indx < 10000; ++indx) {
     // start with "Picture-1.jpg" after "Picture.jpg" exists
 #ifdef XP_WIN
     SetLeafName(rootName +
                 NS_ConvertASCIItoUTF16(nsPrintfCString("-%d", indx)) +
                 suffix);
 #else
     SetNativeLeafName(rootName + nsPrintfCString("-%d", indx) + suffix);
 #endif
     rv = Create(aType, aAttributes);
-    if (NS_SUCCEEDED(rv) || rv != NS_ERROR_FILE_ALREADY_EXISTS) {
+    if (NS_SUCCEEDED(rv) || !FailedBecauseExists(rv)) {
       return rv;
     }
   }
 
   // The disk is full, sort of
   return NS_ERROR_FILE_TOO_BIG;
 }