If you have a Windows machine, this could be a valid dialog. If you have your Flash Player configured to notify you when an update is available, when Flash finds an update is available it creates a registry entry to display the notification upon log in. If you'd like to verify if this is valid, please take a screenshot of the dialog window and post it here. Also, when the dialog displays, open Task Manager and look for a FlashUtil_VersionNumber.exe process. Get the exact file name and post it here as well.
Alternatively, you can update Flash Player on your own by going to get.adobe.com/flashplayer. Once Flash Player is updated you should not receive any more updates (unless you elect to receive notifications at which point, the notification will display when an update is available). If you use multiple browsers, you'll want to visit this page with each browser, as it's configured to detect the OS/browser and offer the appropriate player type depending on the browser.
Thanks for your quick response to my question. As I am not currently at
my own computer, I cannot say if I received an update notice today.
However, I will send you a screen shot of one as soon as actually
Your explanation has given me some comfort that I am probably receiving
the update notice from Adobe rather than some unsolicited and
You're welcome, Tom. For notification updates, Flash Player doesn't check for an update daily, so it may be a few days before you see the notification again.