1 files changed, 2 insertions, 1 deletions
diff --git a/src/alf.c b/src/alf.c
index 49e69c2..88cb316 100644
--- a/src/alf.c
+++ b/src/alf.c
@@ -143,7 +143,8 @@ unsigned long get_msdos_date_time(void) {
 
 	msdos_year = tm->tm_year + 1900 - 1980;
 
-	ms_date = tm->tm_mday | (tm->tm_mon << 5) | (msdos_year << 9);
+	/* tm_mon + 1 because MS uses 1-12 for months, and struct tm uses 0-11 */
+	ms_date = (tm->tm_mday) | (((tm->tm_mon + 1) << 5)) | (msdos_year << 9);
 	ms_time = (tm->tm_sec >> 1) | (tm->tm_min << 5) | (tm->tm_hour << 11);
 	return ms_date | (ms_time << 16);
 }