Solidworks Host File Block !full! Jun 2026

Discussions surrounding the "SolidWorks Host File Block" often revolve around IT workarounds for license activation issues or PDM connectivity problems, rather than a single "product review." Here are the most interesting and common insights found regarding modifying the Windows hosts file for SolidWorks: 1. PDM Server Connection Savior A common, yet sometimes risky, technique is using the Windows hosts file ( C:\Windows\System32\drivers\etc\hosts ) to map the PDM server name to a specific IP address. GoEngineer The Review/Scenario: When client workstations cannot resolve the PDM server name due to DNS issues, editing the hosts file enables direct communication. The Catch: Experts warn this should be a fix. Long-term use of this workaround can lead to issues with network mapping and server maintenance. GoEngineer 2. SNL License Server Troubleshooting For companies using SolidNetWork License (SNL) Manager, editing the hosts file is often necessary when the server hostname is not properly resolved across a VPN or complex network. The Review/Scenario: It is essential to ensure that when adding the IP address and server name, there is in front of the line, as this makes it a comment. Add the server's IP address, followed by a tab or space, and then the server hostname to establish the connection mapping. 3. "No Internet" Activation Workaround Some users in air-gapped environments or behind strict firewalls use the hosts file to block outbound connection attempts to SolidWorks licensing servers, forcing a manual activation process. SolidWorks The Review/Scenario: While this works, it requires manual maintenance if the IP addresses of the licensing servers change. 4. Important Considerations Admin Rights Required: To edit the hosts file, Notepad must be opened as an administrator. Firewall Conflicts: Sometimes a firewall is the culprit rather than DNS. Before editing the hosts file, verify that TCP ports 25734 and 25735 are open for SNL communication. Risk of Misconfiguration: Manually mapping host files, if not done precisely, can cause connectivity issues for other software or lead to confusion if the server IP changes in the future. GoEngineer

In SOLIDWORKS , a "Host File Block" typically refers to a critical diagnostic workaround involving the modification of the Windows hosts file to resolve connectivity or performance issues between a workstation and a SOLIDWORKS PDM server. This technical intervention is primarily used when Domain Name System (DNS) failures prevent a computer from correctly translating a server's name into its IP address, causing the PDM client to hang or fail. Why the Host File is Blocked or Modified The Windows hosts file serves as a local "address book" that the operating system checks before reaching out to external DNS servers. In a SOLIDWORKS environment, this file is used to: Resolve Connection Lag : High latency in DNS resolution can cause massive slowdowns when opening or saving files in PDM. Manually mapping the server IP to its name in the hosts file bypasses this delay. Bypass DNS Failures : If the PDM Archive or Database server cannot be found by its name, adding it to the hosts file ensures the client connects directly to the correct IP. Identify Security Blocks : Antivirus programs (like SentinelOne, ZoneAlarm, or Webroot) often "block" the ability to write to the hosts file to prevent malware from redirecting traffic. These blocks must be temporarily disabled to apply the SOLIDWORKS fix. How to Configure the SOLIDWORKS PDM Host File To implement this workaround, follow these steps to ensure the file is correctly updated and not being blocked by system permissions: Launch Notepad as Administrator : Navigate to the Start menu, search for Notepad, right-click it, and select Run as Administrator . Open the Hosts File : Go to File > Open . Navigate to: C:\Windows\System32\drivers\etc\ . Change the file type filter in the bottom right from Text Documents (*.txt) to All Files to see the hosts file (it has no extension). Add Server Entries : On a new line at the bottom of the file, enter the server's IP address, followed by a tab or space, and then the server name. Example: 192.168.1.100 PDM-SERVER-01 Save and Verify : Save the file. If Windows denies saving, right-click the hosts file in File Explorer, select Properties , and ensure Read-only is unchecked. Troubleshooting Common Blocks If you are unable to save the changes or the fix doesn't work, consider these common "blocks": Antivirus Interference : Check your security software settings. For instance, in Webroot , you may need to uncheck "Prevent any program from modifying the HOSTs file". Read-Only Attributes : Ensure the file is not locked by the system or another open application. DNS Flush : After saving, open a Command Prompt and type ipconfig /flushdns to ensure the system recognizes the new local mapping. Note : This modification is intended as a temporary diagnostic tool or a short-term workaround. For long-term stability, it is recommended to work with your IT department to resolve the underlying DNS issues within the network infrastructure.

SolidWorks Host File Block Overview A SolidWorks host file block is a change to the operating system’s hosts file that prevents SolidWorks (or its license manager) from communicating with a license server or activation service by redirecting specific hostnames to a local or invalid IP address. This is sometimes used as a troubleshooting step or to control network license behavior, but it can cause licensing failures, feature limitations, or violate license agreements if used to bypass protections. How it works (technical)

The hosts file maps hostnames to IP addresses before DNS is queried. On Windows it’s located at: Solidworks Host File Block

C:\Windows\System32\drivers\etc\hosts

A host file block adds lines like:

127.0.0.1 license.solidworks.com 0.0.0.0 swactivate.solidworks.com The Catch: Experts warn this should be a fix

When the SolidWorks client or FlexNet license manager tries to resolve those hostnames, it receives the redirected IP and cannot reach the real server, causing communication to fail.

Common reasons users encounter host file blocks

Manual editing to try to disable online activation or telemetry. Security or privacy tools that automatically block known vendor telemetry or activation domains. Malware or third-party scripts that alter hosts for other reasons. Corporate IT policies that restrict access to external services. but it can cause licensing failures

Typical symptoms when SolidWorks is affected

License activation or renewal fails. “Unable to reach license server” or “No license found” errors. Features that require online verification are disabled. Error messages referencing specific hostnames or network timeouts.