Blocking SolidWorks' access to its activation and telemetry servers is a precise process that requires administrative privileges.
The hosts file is used by Windows to map specific hostnames to IP addresses. Sometimes, security software or previous manual edits add entries that "blackhole" (redirect to 127.0.0.1 ) SOLIDWORKS licensing or update domains, preventing the installer from verifying your serial number. How to Fix It:
If you find that SOLIDWORKS or other software keeps modifying your hosts file, you can change the file permissions to read-only: Right-click the hosts file and select . Go to the Security tab.
If a computer previously hosted an unauthorized or pirated version of SolidWorks (or other CAD software), automated crack scripts frequently modify the hosts file to block activation checks. When you attempt to transition to a legitimate, licensed version, these old blocks remain and prevent the official Installation Manager from verifying the serial number.