What a Troublemaker Helpsupport.usa.cc is!
Helpsupport.usa.cc pop-up actually is a tech support scam used to help the swindlers to promote their services or products. If you are stuck at the same nuisance, you may always get a Mac Security Warning pop-up with the URL pointing to Helpsupport.usa.cc/index.html locking up your screen and claiming that you need a password to login in. Its background will be a BSoD warning reporting: "The problem is caused by an unusual activity performed on this machine. Error code: KSCQF. Call customer support number 1-866-711-4990 and share this code with the agent…". Never be fooled!
