diff --git a/imap-send.c b/imap-send.c
index 285ad29afb4..94e39cd94cb 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -93,7 +93,7 @@ typedef struct {
 	char *data;
 	int len;
 	unsigned char flags;
-	unsigned char crlf:1;
+	unsigned int crlf:1;
 } msg_data_t;
 
 #define DRV_OK          0