As of today, Google AdWords is deactivating accounts that have no ad spend within the past 15 months. This will be done automatically and users will receive (if you haven’t already) an email notification letting you know.
According to Google AdWords, this move is to speed up the overall AdWords experience. This also coincides with the upcoming release of the new AdWords interface. It makes you wonder how memory intensive the new interface is if they have to resort to moves like this.
The good news for those affected is that you still have the ability to reactivate the account if you have been deactivated. Simply sign in to AdWords, go to your settings and the preferences tab and voila, you will see “reactivate account”