Edge 840, data corruption after long ride (about 8 hrs)

When I finish a long ride about 8 hrs, I just press stop & save. Not to answer the questions about water , calories, feel difficult level and etc. and then press power button. About 3 hrs later, I want to check ride data and press power key. And then found the data is not recognized. 

Any solution to recovery back?

when click that and it runs circle all the time 

  • The ride isn't saved until you've answered the questions.  Therefore, if you turn off before that you risk corrupting the data, which is what might have happened here.  

    You may have to manually delete this ride. But for future rides, if you don't value the additional questions you can turn them all off. 

  • I totally do not agree. Since there is a ’SAVE’ button before you answer those questions, it means your ride data is saved.  And the device is suspended, not power off, or battery run out. The ride data should be kept until the user finish those questions. 

    THIS IS GARMIN PROBLEM.

    your reply imply this is my fault. I could not accept this.