diff -up mtools-4.0.43/mcopy.c.orig mtools-4.0.43/mcopy.c
--- mtools-4.0.43/mcopy.c.orig	2024-08-20 18:41:43.957181199 +0200
+++ mtools-4.0.43/mcopy.c	2024-08-20 18:40:51.921966014 +0200
@@ -196,7 +196,8 @@ static int _unix_write(MainParam_t *mp,
 	Stream_t *File=mp->File;
 	Stream_t *Target, *Source;
 	struct MT_STAT stbuf;
-	char errmsg[80];
+	/* matches buffer size in SimpleFileOpenWithLm() */
+	char errmsg[200];
 
 	File->Class->get_data(File, &mtime, 0, 0, 0);