If you follow this guide exactly, you will resolve the yellow triangle, recover your license server connection, and get back to engineering. However, if the error persists after three attempts, the problem is likely not the Hosts file—it is your network firewall, your license server hardware ID mismatch, or a corrupt .lic file.
After saving, clear your local cache to ensure the new settings take effect immediately. Command Prompt ipconfig /flushdns PDM Connectivity Test Tool or a simple ping [Server Name] to confirm the connection is active. Troubleshooting Host File "Blocks" If you cannot save the file even as an administrator: Antivirus Interference: Software like SentinelOne
Scroll to the bottom of the file and paste the following lines. These cover the primary SolidWorks domains and license server addresses. solidworks host file block fix
Replies from 127.0.0.1 (your own PC). If you see an actual IP address → the host file is not being read.
Disclaimer: This guide is intended for resolving issues on legally licensed installations of SolidWorks. Modifying the hosts file to bypass licensing mechanisms is against the terms of service. If you follow this guide exactly, you will
Navigate to the following path: C:\Windows\System32\drivers\etc Locate the file named . Step 2: Editing the Hosts File to Remove Blocks
Go to Control Panel > Internet Options > Connections > LAN Settings and ensure "Automatically detect settings" is checked. Conclusion Command Prompt ipconfig /flushdns PDM Connectivity Test Tool
If an incorrect entry or a loopback address (like 127.0.0.1 ) is attached to a SolidWorks server address in this file, your computer blocks itself from reaching the real license server. This happens due to aggressive antivirus scripts, improper network migrations, or malware cleanup leftovers. Step 1: Locate and Open the Windows Host File
In this 2,500+ word guide, we will dissect exactly what the Hosts file does, why SolidWorks modifies its behavior regarding it, the step-by-step fix, and—most importantly—how to prevent this from happening during a critical deadline.
The splash screen appeared. Initialising... Loading Registry... and then, with a triumphant chime, the interface bloomed into life. The assembly for Project Chimera loaded in all its complex, geometric glory.
Open the and navigate to System and Security > Windows Defender Firewall . Click Advanced Settings on the left panel.