diff --git a/targets/TARGET_STM/rtc_api.c b/targets/TARGET_STM/rtc_api.c
index 3be15602c6..fe6239177e 100644
--- a/targets/TARGET_STM/rtc_api.c
+++ b/targets/TARGET_STM/rtc_api.c
@@ -64,6 +64,7 @@ void rtc_init(void)
     HAL_PWR_EnableBkUpAccess();
 
     RtcHandle.Instance = RTC;
+    RtcHandle.State = HAL_RTC_STATE_RESET;
 
 #if !RTC_LSI
     RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;