Unfortunately, there’s no sure-fire way to stop those “Updates Available” notifications from appearing in the top-right corner of your Mac other than just keeping your software up to date! Of course, you can always click and drag the notification out off of the right side of the desktop to temporarily get it off the screen. If you forgot your Apple ID password, go to to reset it. Sign out and sign in again with the same Apple ID and Password.
Sign In again using your Apple ID and Password.Click Sign Out in the bottom lefthand corner of the iCloud preferences window.
Usually, the reason this happens is that you changed your password or email address associated with your Apple ID recently (but it could be a variety of reasons). The real confusing part is that these popups often occur even when the user is not trying to access anything related to iCloud. This also occurs with Messages and FaceTime. Occasionally, some users will report repeating popups asking for their iCloud Password. Simply doing this solved the problem for me, please let us know in the comments below if this doesn’t do the trick! iCloud Password