Solidworks Host File Block Fix [better] Jun 2026

: Programs like Webroot , ZoneAlarm , and SentinelOne often protect the hosts file from being modified.

The Windows Hosts file is a plain text file used by the operating system to map human-readable hostnames to numerical IP addresses. It acts as a local phone book for your network connections, overriding external Domain Name System (DNS) lookups.

: After saving, open the Command Prompt and type ipconfig /flushdns to clear old resolution data. Related Fixes for Common SOLIDWORKS Blocks

If the Hosts file is clear but you still face blocks, your firewall may be preventing the connection.

Are you experiencing a specific (like -15 or -8) that led you to the hosts file? 11 SOLIDWORKS CTRL Key Shortcuts to Start Using Today solidworks host file block fix

Open Command Prompt as Administrator. Step 2: Type ping licensing.solidworks.com Step 3: Look at the result.

: On a new line at the bottom, type the Server IP address , hit Tab, and then type the Server Name . Example: 192.168.1.50 PDM-Server-01 .

Note: Ensure there is a space or a tab between the numbers and the text, and do not include any # symbols at the beginning of these lines, as # tells Windows to ignore the line. Step 4: Save and Close Click , then select Save (or press Ctrl + S ). Close Notepad. Step 5: Flush Your DNS Cache

How to Fix SolidWorks Activation Issues Caused by Host File Blocks : Programs like Webroot , ZoneAlarm , and

There it was. At the very bottom of the text file, a series of lines had been added. They were redirecting the SolidWorks licensing URLs to 127.0.0.1 —the digital equivalent of a dead-end street.

By default, Notepad only looks for text files. Click the dropdown menu in the bottom-right corner of the Open dialog box (above the Open button) and change it from to All Files ( . ) .

If the hosts file edit doesn't work, the "block" might be elsewhere:

In the bottom-right corner of the open dialog, change the file type filter from Text Documents (*.txt) to All Files ( . ) so the hosts file becomes visible. Edit the File Scroll to the bottom of the file. : After saving, open the Command Prompt and

While the list varies, common target domains include:

Ensure inbound and outbound rules allow traffic for SLDWORKS.exe .

He saved the file, closed the window, and held his breath.

If your hosts file contains lines related to solidworks.com or dassaultsystemes.com that map to 127.0.0.1 (your own computer), the activation request will never leave your machine, resulting in a or invalid license error . How to Diagnose a Host File Block