SOLIDWORKS installation failures or hangs, particularly during activation, can often be resolved by removing blocks for solidworks.com domains within the Windows "hosts" file [1]. Users should open Notepad as an administrator, locate the file at C:\Windows\System32\drivers\etc, remove lines referencing solidworks.com, and save the file to restore connectivity [1].

Phase 5: The "Compatibility" Installation

Now, when you run the SolidWorks setup.exe:

1. Disable your Wi-Fi or unplug the Ethernet cable. (Double-blocking is safe).
2. Run the installer.
3. When asked for activation, select "I have a serial number" (do not try to activate online).
4. If using a network license, point the installer to 25734@YourServerName (do not use the internet address).
5. Complete the install.

You have successfully performed a SolidWorks host file block install.

Alternative Methods: Beyond the Hosts File

While the hosts file is simple, it is also easy for SolidWorks to bypass (some versions ignore hosts entries for critical domains). More robust alternatives include:

1. Windows Firewall with Advanced Security:
   Create outbound rules blocking sw_d.exe, swactwiz.exe, and sldworks.exe.

2. Hardware Firewall / Router:
   Block all traffic to/from Dassault Systèmes ASN ranges at the network level.

3. Virtual Machine with Disabled Network Adapter:
   Install SolidWorks inside a VM that has no virtual network adapter.

4. DNS Filtering (Pi-hole, etc.):
   Block the domains at the DNS resolver level for the entire network.

Legality

Read your SolidWorks EULA (End User License Agreement). Most clauses state:

"You shall not... attempt to circumvent the technical limitations of the Software."

By blocking activation servers, you are technically circumventing a technical limitation—even if you own a perpetual license. In the event of an audit (Dassault is known for aggressive BSA audits), a modified hosts file is a red flag. Keep your purchase receipts handy.

The "Block" Explained

The "block" refers to redirecting these specific domain names back to your own computer (127.0.0.1 or 0.0.0.0). By doing a SolidWorks host file block install, you prevent the software from verifying the license status externally.

Crucial Disclaimer: This article assumes you are using a legitimately purchased license. Blocking outbound calls is legal for privacy and stability when you have a perpetual license key. This guide does not condone software piracy. Using these methods to crack software is illegal and dangerous.

Network License Manager (FLEXnet) Servers

127.0.0.1 sw_d.licensing.solidworks.com 127.0.0.1 sw_d.solidworks.com

Part 1: What is the Hosts File and Why Does SolidWorks Care?

For Network Floating Licenses (SNL)

Blocking the hosts file on a SolidWorks Network License Manager server is not recommended. The server needs to communicate with Dassault to manage borrowing and compliance. Instead, block only on client workstations to prevent them from bypassing the license server.