License Keys questions and issues

How to execute an offline activation 'Another instance of ReSharper with the same License' error message I would like to purchase or upgrade ReSharper license. What should I do? What License Information should be used for ReSharper EAP builds? I've lost my License Key. How do I recover it? How can I completely remove the License Information from the PC? 'License Key is Invalid' error when registering ReSharper (ReSharper 4.x - 8.x) How to fix error "This site can’t provide a secure connection" when trying to log in to JetBrains account