diff --git a/reactos/include/ndk/rtltypes.h b/reactos/include/ndk/rtltypes.h
index c211ccada3c..3b932372ca9 100644
--- a/reactos/include/ndk/rtltypes.h
+++ b/reactos/include/ndk/rtltypes.h
@@ -1012,7 +1012,7 @@ typedef struct _CURDIR
     HANDLE Handle;
 } CURDIR, *PCURDIR;
 
-typedef struct RTL_DRIVE_LETTER_CURDIR
+typedef struct _RTL_DRIVE_LETTER_CURDIR
 {
     USHORT Flags;
     USHORT Length;
@@ -1020,6 +1020,13 @@ typedef struct RTL_DRIVE_LETTER_CURDIR
     UNICODE_STRING DosPath;
 } RTL_DRIVE_LETTER_CURDIR, *PRTL_DRIVE_LETTER_CURDIR;
 
+typedef struct _RTL_PERTHREAD_CURDIR
+{
+    PRTL_DRIVE_LETTER_CURDIR CurrentDirectories;
+    PUNICODE_STRING ImageName;
+    PVOID Environment;
+} RTL_PERTHREAD_CURDIR, *PRTL_PERTHREAD_CURDIR;
+
 //
 // Private State structure for RtlAcquirePrivilege/RtlReleasePrivilege
 //