"This device is not linked to your account"

Hello Janos, 

We are sorry for the inconvenience caused. We will check and help you to resolve it. Could you please share us the screenshot of the page which shows " this device is not linked to your account"? 

You can post the screenshot here in your topic. Click on Answer & then click on the Image [mountain symbol] & follow the instructions. Thanks in advance.

Why after months of fine operation with Internet Security, suddenly this note about "linking to the account" and the requirement to log in? Is it legit and if so, why does it happen?

Hello Janos, 

Thank you for writing back to us. If you have logged in to AVG MyAccount on installed AVG programs, you can just ignore the message. Please follow the steps below to check whether AVG program logged in with AVG Myaccount :

Open AVG program - Click on Menu  - Click on MySubscription. 

If you have already logged in with AVG MyAccount, It will show email address in the Mysubscription page. Else, you can see option to login with AVG MyAccount. So, you can use your credentials to login with MyAccount. 

If you have any clarification, please do let us know.

Hi. Thank you for the prompt response. 
Before taking any more time with this, what I want to be clear about if the "This device is not linked to your account" message came from AVG and if I comply with it, nothikng untoward will happen. 
I received the message both on a laptop and the desktop, a few days apart, and when I tried to comply with the instruction to log in, my password was not accepted so I changed it, and nothing happened after that. 
On the desktop, I ignored the message - and nothing hapened. 
At his point, I don't have the original message which appeared as part of AVG.