Windows login password suddenly stopped working

[BostonFern]

I was able to log into my Windows 10 around noon today. 2 hours later, I could no longer log in. Each time I tried, it told me my password was incorrect. I ended up having to reset my password through my smart phone.

I'm wondering why. Is there anyway for me to see when my password was changed in the past?

 

[Regedit32]

Hi Boston,

The Windows Event Viewer accessed by right-clicking on Start then left-clicking on Event Viewer may contain a log of the event.

When opened in the left pane you need to expand Windows Logs then click Security.

Sample image

Now in middle pane look for Event IDs:

• 4273 (An attempt was made to change password) or,
• 4274 (An attempt was made to reset password)
• It may also fall under the generic 4797 id for Account Management.
  
  The items are date and time stamped which will help if you have a rough idea of when you believe password changed.

Regards,

Regedit32