diff --git a/include/wine/server_protocol.h b/include/wine/server_protocol.h
index 1b7831e73cc..0205131fb5b 100644
--- a/include/wine/server_protocol.h
+++ b/include/wine/server_protocol.h
@@ -4845,7 +4845,7 @@ struct create_completion_request
     unsigned int attributes;
     unsigned int concurrent;
     obj_handle_t rootdir;
-    /* VARARG(filename,string); */
+    /* VARARG(filename,unicode_str); */
     char __pad_28[4];
 };
 struct create_completion_reply
@@ -4863,7 +4863,7 @@ struct open_completion_request
     unsigned int access;
     unsigned int attributes;
     obj_handle_t rootdir;
-    /* VARARG(filename,string); */
+    /* VARARG(filename,unicode_str); */
 };
 struct open_completion_reply
 {
diff --git a/server/protocol.def b/server/protocol.def
index 2cd82725ef0..a34dde952eb 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -3366,7 +3366,7 @@ enum coords_relative
     unsigned int attributes;      /* object attributes */
     unsigned int concurrent;      /* max number of concurrent active threads */
     obj_handle_t rootdir;         /* root directory */
-    VARARG(filename,string);      /* port name */
+    VARARG(filename,unicode_str); /* port name */
 @REPLY
     obj_handle_t handle;          /* port handle */
 @END
@@ -3377,7 +3377,7 @@ enum coords_relative
     unsigned int access;          /* desired access to a port */
     unsigned int attributes;      /* object attributes */
     obj_handle_t rootdir;         /* root directory */
-    VARARG(filename,string);      /* port name */
+    VARARG(filename,unicode_str); /* port name */
 @REPLY
     obj_handle_t handle;          /* port handle */
 @END
diff --git a/server/trace.c b/server/trace.c
index c7f49219edc..e5d3cd35c38 100644
--- a/server/trace.c
+++ b/server/trace.c
@@ -3951,7 +3951,7 @@ static void dump_create_completion_request( const struct create_completion_reque
     fprintf( stderr, ", attributes=%08x", req->attributes );
     fprintf( stderr, ", concurrent=%08x", req->concurrent );
     fprintf( stderr, ", rootdir=%04x", req->rootdir );
-    dump_varargs_string( ", filename=", cur_size );
+    dump_varargs_unicode_str( ", filename=", cur_size );
 }
 
 static void dump_create_completion_reply( const struct create_completion_reply *req )
@@ -3964,7 +3964,7 @@ static void dump_open_completion_request( const struct open_completion_request *
     fprintf( stderr, " access=%08x", req->access );
     fprintf( stderr, ", attributes=%08x", req->attributes );
     fprintf( stderr, ", rootdir=%04x", req->rootdir );
-    dump_varargs_string( ", filename=", cur_size );
+    dump_varargs_unicode_str( ", filename=", cur_size );
 }
 
 static void dump_open_completion_reply( const struct open_completion_reply *req )