diff --git a/core/sys/windows/kernel32.odin b/core/sys/windows/kernel32.odin
index 114e70b41..ff27cf795 100644
--- a/core/sys/windows/kernel32.odin
+++ b/core/sys/windows/kernel32.odin
@@ -413,6 +413,7 @@ foreign kernel32 {
 		lpBytesLeftThisMessage: ^u32,
 	) -> BOOL ---
 	CancelIo :: proc(handle: HANDLE) -> BOOL ---
+	CancelIoEx :: proc(hFile: HANDLE, lpOverlapped: LPOVERLAPPED) -> BOOL ---
 	GetOverlappedResult :: proc(
 		hFile: HANDLE,
 		lpOverlapped: LPOVERLAPPED,
@@ -554,6 +555,7 @@ foreign kernel32 {
 	GetHandleInformation :: proc(hObject: HANDLE, lpdwFlags: ^DWORD) -> BOOL ---
 
 	RtlCaptureStackBackTrace :: proc(FramesToSkip: ULONG, FramesToCapture: ULONG, BackTrace: [^]PVOID, BackTraceHash: PULONG) -> USHORT ---
+	RtlNtStatusToDosError :: proc(status: NTSTATUS) -> ULONG ---
 
 	GetSystemPowerStatus :: proc(lpSystemPowerStatus: ^SYSTEM_POWER_STATUS) -> BOOL ---
 }
diff --git a/core/sys/windows/winerror.odin b/core/sys/windows/winerror.odin
index 05ab3d028..23467761d 100644
--- a/core/sys/windows/winerror.odin
+++ b/core/sys/windows/winerror.odin
@@ -222,9 +222,11 @@ ERROR_LOCK_FAILED            : DWORD : 167
 ERROR_ALREADY_EXISTS         : DWORD : 183
 ERROR_NO_DATA                : DWORD : 232
 ERROR_ENVVAR_NOT_FOUND       : DWORD : 203
+ERROR_MR_MID_NOT_FOUND       : DWORD : 317
 ERROR_OPERATION_ABORTED      : DWORD : 995
 ERROR_IO_PENDING             : DWORD : 997
 ERROR_NO_UNICODE_TRANSLATION : DWORD : 1113
+ERROR_NOT_FOUND              : DWORD : 1168
 ERROR_TIMEOUT                : DWORD : 1460
 ERROR_DATATYPE_MISMATCH      : DWORD : 1629
 ERROR_UNSUPPORTED_TYPE       : DWORD : 1630