--- a/xpcom/build/mozPoisonWriteWin.cpp
+++ b/xpcom/build/mozPoisonWriteWin.cpp
@@ -19,26 +19,16 @@ intptr_t FileDescriptorToID(int aFd) {
   return _get_osfhandle(aFd);
 }
 
 static WindowsDllInterceptor sNtDllInterceptor;
 
 void AbortOnBadWrite(HANDLE);
 bool ValidWriteAssert(bool ok);
 
-typedef NTSTATUS (WINAPI* FlushBuffersFile_fn)(HANDLE, PIO_STATUS_BLOCK);
-FlushBuffersFile_fn gOriginalFlushBuffersFile;
-
-NTSTATUS WINAPI
-patched_FlushBuffersFile(HANDLE aFileHandle, PIO_STATUS_BLOCK aIoStatusBlock)
-{
-  AbortOnBadWrite(aFileHandle);
-  return gOriginalFlushBuffersFile(aFileHandle, aIoStatusBlock);
-}
-
 typedef NTSTATUS (WINAPI* WriteFile_fn)(HANDLE, HANDLE, PIO_APC_ROUTINE,
                                         void*, PIO_STATUS_BLOCK,
                                         const void*, ULONG, PLARGE_INTEGER,
                                         PULONG);
 WriteFile_fn gOriginalWriteFile;
 
 static NTSTATUS WINAPI
 patched_WriteFile(HANDLE aFile, HANDLE aEvent, PIO_APC_ROUTINE aApc,
@@ -88,14 +78,13 @@ void PoisonWrite() {
   if (WritesArePoisoned)
     return;
   WritesArePoisoned = true;
 
   if (!PoisonWriteEnabled())
     return;
 
   sNtDllInterceptor.Init("ntdll.dll");
-  sNtDllInterceptor.AddHook("NtFlushBuffersFile", reinterpret_cast<intptr_t>(patched_FlushBuffersFile), reinterpret_cast<void**>(&gOriginalFlushBuffersFile));
   sNtDllInterceptor.AddHook("NtWriteFile", reinterpret_cast<intptr_t>(patched_WriteFile), reinterpret_cast<void**>(&gOriginalWriteFile));
   sNtDllInterceptor.AddHook("NtWriteFileGather", reinterpret_cast<intptr_t>(patched_WriteFileGather), reinterpret_cast<void**>(&gOriginalWriteFileGather));
 }
 }