The Federal Trade Commission and the Florida attorney general’s office reached settlements totaling about $48.7 million with tech support companies accused of selling worthless computer cleanup software, the agencies announced Friday.

The agencies claimed Boston-based Boost Software Inc. advertised its software could make computers run faster and protect them from errors, crashes and freezes. Consumers would download a free version of the PC HealthBoost software, which would sent an alert warning there were “hundreds or thousands of errors in need of repair” even if there weren’t, the FTC and attorney general’s office alleged.