diff --git a/ext/mime_magic/mime_magic.c b/ext/mime_magic/mime_magic.c
index 6e5b308fb9f..89138d8764f 100644
--- a/ext/mime_magic/mime_magic.c
+++ b/ext/mime_magic/mime_magic.c
@@ -348,7 +348,7 @@ static int apprentice(void)
     magic_server_config_rec *conf = &mime_global;
 
     fname = conf->magicfile; /* todo cwd? */
-    f = fopen(fname, "rt");
+    f = fopen(fname, "rb");
     if (f == NULL) {
 		(int) conf->magic = -1;
 		return -1;