diff --git a/xpcom/reflect/xptinfo/src/xptiManifest.cpp b/xpcom/reflect/xptinfo/src/xptiManifest.cpp
index f2a9e80e3f2..21891aac69a 100644
--- a/xpcom/reflect/xptinfo/src/xptiManifest.cpp
+++ b/xpcom/reflect/xptinfo/src/xptiManifest.cpp
@@ -131,6 +131,7 @@ PRBool xptiManifest::Write(xptiInterfaceInfoManager* aMgr,
     PRUint32 size32;
     PRIntn interfaceCount = 0;
     nsCAutoString appDirString;
+    nsCOMPtr<nsIFile> greDirectory;
     
     nsCOMPtr<nsILocalFile> tempFile;
     if(!aMgr->GetCloneOfManifestDir(getter_AddRefs(tempFile)) || !tempFile)
@@ -177,6 +178,8 @@ PRBool xptiManifest::Write(xptiInterfaceInfoManager* aMgr,
                        (int) aWorkingSet->GetDirectoryCount()))
         goto out;
 
+    NS_GetSpecialDirectory(NS_GRE_COMPONENT_DIR, getter_AddRefs(greDirectory));
+
     for(i = 0; i < aWorkingSet->GetDirectoryCount(); i++)
     {
         nsCOMPtr<nsILocalFile> dir;        
@@ -186,9 +189,19 @@ PRBool xptiManifest::Write(xptiInterfaceInfoManager* aMgr,
         if(!dir)
             goto out;
 
-        dir->GetPersistentDescriptor(str);
-        if(str.IsEmpty())
-            goto out;
+        PRBool isGREDir = PR_FALSE;
+        if (greDirectory)
+            dir->Equals(greDirectory, &isGREDir);
+
+        if (isGREDir) {
+            str = "gre";
+        }
+        else 
+        {
+            dir->GetPersistentDescriptor(str);
+            if(str.IsEmpty())
+                goto out;
+        }
         
         if(!PR_fprintf(fd, "%d,%s\n", (int) i, str.get()))
             goto out;
@@ -491,6 +504,8 @@ PRBool xptiManifest::Read(xptiInterfaceInfoManager* aMgr,
 
     for(i = 0; i < dirCount; ++i)
     {
+        nsCAutoString str;
+
         if(!reader.NextLine())
             goto out;
        
@@ -502,8 +517,23 @@ PRBool xptiManifest::Read(xptiInterfaceInfoManager* aMgr,
         if(i != atoi(values[0]))
             goto out;
 
+        if (0 != PL_strcmp(values[1], "gre"))
+        {
+            nsCOMPtr<nsIFile> greDirectory;
+            NS_GetSpecialDirectory(NS_GRE_COMPONENT_DIR, getter_AddRefs(greDirectory));
+            nsCOMPtr<nsILocalFile> lFile = do_QueryInterface(greDirectory);
+            if (!lFile)
+                goto out;
+
+            lFile->GetPersistentDescriptor(str);
+        }
+        else
+        { 
+            str = values[1];
+        }            
+
         // directoryname
-        if(!aWorkingSet->DirectoryAtMatchesPersistentDescriptor(i, values[1]))
+        if(!aWorkingSet->DirectoryAtMatchesPersistentDescriptor(i, str.get()))
             goto out;    
     }