diff --git a/dll/win32/kernel32/client/proc.c b/dll/win32/kernel32/client/proc.c
index 9b680eb533..3bf943ba58 100644
--- a/dll/win32/kernel32/client/proc.c
+++ b/dll/win32/kernel32/client/proc.c
@@ -1659,7 +1659,9 @@ WINAPI
 GetPriorityClass(IN HANDLE hProcess)
 {
     NTSTATUS Status;
-    PROCESS_PRIORITY_CLASS PriorityClass;
+    PROCESS_PRIORITY_CLASS DECLSPEC_ALIGN(4) PriorityClass;
+
+    if ((INT)hProcess == 0xFFFFFFFF) return 0;
 
     /* Query the kernel */
     Status = NtQueryInformationProcess(hProcess,
@@ -1696,7 +1698,7 @@ SetPriorityClass(IN HANDLE hProcess,
 {
     NTSTATUS Status;
     PVOID State = NULL;
-    PROCESS_PRIORITY_CLASS PriorityClass;
+    PROCESS_PRIORITY_CLASS DECLSPEC_ALIGN(4) PriorityClass;
 
     /* Handle conversion from Win32 to NT priority classes */
     switch (dwPriorityClass)