diff --git a/dlls/dbghelp/dbghelp.c b/dlls/dbghelp/dbghelp.c
index a085cd140ef..ed4d5f4321f 100644
--- a/dlls/dbghelp/dbghelp.c
+++ b/dlls/dbghelp/dbghelp.c
@@ -310,7 +310,7 @@ BOOL WINAPI SymInitializeW(HANDLE hProcess, PCWSTR UserSearchPath, BOOL fInvadeP
 
     IsWow64Process(GetCurrentProcess(), &wow64);
 
-    if (!IsWow64Process(hProcess, &child_wow64))
+    if (GetProcessId(hProcess) && !IsWow64Process(hProcess, &child_wow64))
         return FALSE;
 
     pcs = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(*pcs));