Why my restore points are disappearing?

Today, I have seen that one windows restore point, the oldest (but only have 10 days) have disappeared. I have enough dedicated disk space for the restore points (yesterday, I had 11.4 Gb occupied of 23 Gb dedicated to restore system), no new one created, I don't have any error warning (event log, reliability monitor, Scanow / sfc, etc), but the point have disappeared by itself. Why ??

dalchina said:

Hi, this question has been asked many times. Could I invite you to search the forum for
disappearing restore points



Here are some of those links... please read through these and more, and then if you have a further question, do please post back..
Disappearing restore points
Restore Points disappearing, Errors in Event Viewer
Missing most of my System Restore Points
Why do my restore points keep vanishing?
System Restore Points Missing

I have read a lot of links about this, but no real solution for me . System restore is activated in services, at default. I have a lot of free space in disk and for restore points (10%, 23 Gb dedicated, only half was used yesterday), no error messages in event log, I have not installed anything today, I am not ussing dual boot, not running any disk cleaning, etc.

But one point missing today.