diff --git a/src/racket/include/schthread.h b/src/racket/include/schthread.h
index e9aab7a002..237ec1a9be 100644
--- a/src/racket/include/schthread.h
+++ b/src/racket/include/schthread.h
@@ -262,6 +262,7 @@ typedef struct Thread_Local_Variables {
   int env_uid_counter_;
   int scheme_overflow_count_;
   struct Scheme_Object *original_pwd_;
+  void *file_path_wc_buffer_;
   intptr_t scheme_hash_request_count_;
   intptr_t scheme_hash_iteration_count_;
   struct Scheme_Env *initial_modules_env_;
@@ -579,6 +580,7 @@ XFORM_GC_VARIABLE_STACK_THROUGH_THREAD_LOCAL;
 #define env_uid_counter XOA (scheme_get_thread_local_variables()->env_uid_counter_)
 #define scheme_overflow_count XOA (scheme_get_thread_local_variables()->scheme_overflow_count_)
 #define original_pwd XOA (scheme_get_thread_local_variables()->original_pwd_)
+#define file_path_wc_buffer XOA (scheme_get_thread_local_variables()->file_path_wc_buffer_)
 #define scheme_hash_request_count XOA (scheme_get_thread_local_variables()->scheme_hash_request_count_)
 #define scheme_hash_iteration_count XOA (scheme_get_thread_local_variables()->scheme_hash_iteration_count_)
 #define initial_modules_env XOA (scheme_get_thread_local_variables()->initial_modules_env_)
diff --git a/src/racket/src/file.c b/src/racket/src/file.c
index fa6a79a6a1..5db8f13f24 100644
--- a/src/racket/src/file.c
+++ b/src/racket/src/file.c
@@ -1153,7 +1153,7 @@ int scheme_os_setcwd(char *expanded, int noexn)
 
 #ifdef DOS_FILE_SYSTEM
 #define WC_BUFFER_SIZE 1024
-static wchar_t wc_buffer[WC_BUFFER_SIZE];
+THREAD_LOCAL_DECL(static void *file_path_wc_buffer);
 
 static int wc_strlen(const wchar_t *ws)
 {
@@ -1174,9 +1174,13 @@ wchar_t *scheme_convert_to_wchar(const char *s, int do_copy)
 			   NULL, 0, -1,
 			   NULL, 1/*UTF-16*/, '\t');
 
-  if (!do_copy && (len < (WC_BUFFER_SIZE-1)))
-    ws = wc_buffer;
-  else
+  if (!do_copy && (len < (WC_BUFFER_SIZE-1))) {
+    if (!file_path_wc_buffer) {
+      REGISTER_SO(file_path_wc_buffer);
+      file_path_wc_buffer = scheme_malloc_atomic(sizeof(wchar_t) * WC_BUFFER_SIZE);
+    }
+    ws = (wchar_t *)file_path_wc_buffer;
+  } else
     ws = (wchar_t *)scheme_malloc_atomic(sizeof(wchar_t) * (len + 1));
   scheme_utf8_decode(s, 0, l,
 		     (unsigned int *)ws, 0, -1,