Solidworks Host File Block — Fix

The Hosts file blocks DNS, but some SolidWorks processes bypass it by using hard-coded IP addresses. You must also block the executable in the firewall.

Instead of manual edits, run the SWIM tool:

If you decide to proceed, here is the correct procedure:

Before we click "Save," let’s understand the battlefield. solidworks host file block fix

The hosts file is a plain text file used by your operating system to map hostnames to IP addresses. It has priority over DNS (Domain Name System). When you type www.google.com, your PC checks the Hosts file first. If it finds an entry, it goes there without asking the internet.

How SolidWorks uses the internet: When you start SolidWorks, it checks for three things:

The "Block" Fix: By editing the Hosts file, you tell your computer to send SolidWorks' validation requests to a dead end (usually 127.0.0.1 - your own computer) instead of the real Dassault servers. The Hosts file blocks DNS, but some SolidWorks

This stops the software from realizing it might be running on a floating license that expired, or prevents it from turning off features because it cannot reach the primary license server.

Push a GPO that:

Blocking activation servers is only legal if you: The "Block" Fix: By editing the Hosts file,

| Problem | Solution | |-------------|---------------| | "Access Denied" when saving | You did not run Notepad as Administrator. | | Changes don't take effect | Windows DNS cache: Reboot or run ipconfig /flushdns. | | SolidWorks still activates | You missed a new server address. Use Wireshark to monitor SolidWorks outbound traffic. | | Internet is slow or broken | You accidentally blocked a critical domain (e.g., windows.com). Remove bad lines. | | Antivirus restores old host file | Add C:\Windows\System32\drivers\etc\hosts to your antivirus exclusion list. |

Rating: 6/10 (Effective but Risky)

The "Host File Block" fix is a workaround, not an official solution. It is highly effective for a specific problem (the "SolidWorks SolidNetwork License Manager cannot connect to the server" error), but it introduces maintenance headaches and potential security risks.

Here is a detailed breakdown of the review.