Solidworks Host File Block Fix [repack] May 2026

The Windows hosts file is a critical system file that maps hostnames to IP addresses, acting as a local DNS override. For SOLIDWORKS users, a "host file block" typically refers to connectivity issues where the software cannot reach the license server or PDM database because of misconfigured entries or security software preventing file modifications. Identifying the Cause of the Block

Before applying a fix, determine if your host file is actually the source of the problem. Common symptoms include:

License Connection Errors: Receiving "Could not obtain a license for SOLIDWORKS" or "License server is down" messages.

PDM Latency: Slow response times when checking files in or out of a PDM vault.

Read-Only Errors: Inability to save changes because the file or its parent folder is marked as "Read-only" at the Windows system level.

Security Interference: Antivirus software (like Webroot or SentinelOne) actively blocking any program from modifying the hosts file. Step-by-Step Fix: Modifying the Hosts File

If your DNS is failing to resolve the server name, you can manually add the server's IP address to the hosts file as a temporary workaround.

Open Notepad as AdministratorClick Start, type Notepad, right-click the application, and select Run as Administrator.

Locate the FileIn Notepad, go to File > Open. Navigate to the following directory:C:\Windows\System32\drivers\etc\Note: Change the file type filter in the bottom-right corner from "Text Documents (.txt)" to All Files (.) to see the hosts file.*

Check for Restricted PermissionsIf you cannot save the file, right-click the hosts file in File Explorer, select Properties, and ensure the Read-only attribute is unchecked.

Add the Server EntryScroll to the bottom of the file and add a new line with the server's IP address, followed by a Tab or space, and then the server name.Example: 192.168.1.100 YOUR_SERVER_NAME.

Save and Flush DNSSave the file. To ensure Windows uses the new entry immediately, open a Command Prompt and type ipconfig /flushdns, then press Enter. Additional Troubleshooting for Persistent Blocks

If editing the hosts file does not restore connectivity, consider these alternative solutions:

How to Configure the Local HOSTS file to Resolve Server Name

The fluorescent lights of the engineering bay hummed with a low, mocking vibrato as Elias stared at the spinning blue cursor on his screen. It was 11:42 PM, and the deadline for the "Project Chimera" prototype was less than eight hours away.

Elias was a veteran designer, the kind who could navigate SolidWorks with his eyes closed. But tonight, the software was a ghost. Every time he tried to launch it, the splash screen would hang on "Verifying License," only to vanish into the digital ether without so much as an error message.

"Come on, you piece of garbage," Elias muttered, his fingers drumming a frantic rhythm on his mahogany desk.

He had already checked the server. He’d restarted his workstation three times. He’d even sacrificed a lukewarm cup of coffee to the silicon gods. Nothing. It was as if his computer had suddenly decided SolidWorks didn't exist.

Desperate, he pulled up his laptop and began a frantic deep-dive into the darker corners of tech forums. He bypassed the official support pages—they were filled with "reinstall the program" advice that he didn't have time for. Finally, on page four of an obscure sysadmin board, he found a thread titled: “The Invisible Wall: When Your System Blocks the Handshake.” The culprit? The Hosts file.

Elias realized that a recent security "patch" from the IT department might have flagged the licensing server’s IP as a suspicious domain. In an effort to keep the network safe, the Windows system had effectively put a blindfold on SolidWorks, preventing it from seeing its own license manager. With a surge of adrenaline, Elias went to work.

The Search: He navigated to the heart of the machine: C:\Windows\System32\drivers\etc.

The Guardian: He right-clicked hosts and opened it with Notepad, but he did it with Administrative privileges—the "skeleton key" of the Windows world.

The Reveal: 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.

The Erasure: With a steady hand, he highlighted the offending lines and hit Delete. He felt like an archaeologist brushing dust off a hidden inscription. solidworks host file block fix

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

He moved his mouse back to the workstation. He double-clicked the red SolidWorks icon.

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.

The "invisible wall" was gone. Elias leaned back, the hum of the lights no longer sounding like a mockery, but a celebration. He had defeated the block, and the prototype was back on track.

Fixing "SolidWorks host file block" issues typically involves unblocking the Windows hosts file from security software or manually editing it to resolve server connection problems. This common technical hurdle often prevents SolidWorks PDM or license managers from communicating with their servers. Common Causes for Host File Blocks

Antivirus/Security Software Interruption: Programs like SentinelOne, ZoneAlarm, and Webroot often lock the hosts file to prevent unauthorized modifications by malware.

File Permissions: The hosts file may be set to "Read-only" or requires administrative privileges to modify.

DNS Resolution Failure: When a network cannot translate server hostnames to IP addresses, the system may need a manual override in the hosts file. Step 1: Unblock the Hosts File from Security Software

Before editing, ensure your security suite is not actively blocking access to C:\Windows\System32\drivers\etc\hosts.

Webroot: Go to settings and uncheck "Prevent any program from modifying the HOSTs file".

ZoneAlarm Firewall: Navigate to Advanced Settings and uncheck "Lock Hosts File".

SentinelOne: A Security Exclusion Policy must be created via the management console to allow writes to the file. Step 2: Clear "Read-Only" Attributes

If the file remains inaccessible even after disabling security blocks: Navigate to C:\Windows\System32\drivers\etc. Right-click the hosts file and select Properties.

Uncheck the Read-only attribute at the bottom of the General tab and click Apply. Step 3: Manually Edit the Hosts File for Server Connection

For SolidWorks PDM or network licenses to work when DNS fails, you must manually point the machine to the correct server IP.

Launch Notepad as Administrator: Search for Notepad in the Start Menu, right-click it, and select Run as Administrator.

Open the File: In Notepad, go to File > Open. Navigate to C:\Windows\System32\drivers\etc\. Ensure the file type filter in the bottom right is set to All Files (.) so the extensionless hosts file appears.

Add Server Entries: Scroll to the bottom and add a new line for each server using the format: [IP Address] [Server Name]. Example: 192.168.1.100 MyPDMVaultServer Save and Close: Save the file. Do not add a .txt extension.

Flush DNS: Open a Command Prompt and type ipconfig /flushdns to ensure the system recognizes the new manual entries immediately. Step 4: Verify the Fix

After unblocking and editing the hosts file, verify the connection using the PDM Connectivity Test Tool or by attempting to ping the server by name in the Command Prompt. If the connection still fails, check if the FlexNet Licensing Service or SolidWorks Licensing Service are running and set to Automatic in Windows Services.

Are you currently facing a specific error code (like -15,10,10061) when trying to connect to your SolidWorks license?

SOLIDWORKS Host File Block Fix: A Comprehensive Guide

Are you experiencing issues with SOLIDWORKS due to a blocked host file? Do you see an error message indicating that the software is unable to connect to the license server or access certain features? You're not alone. In this article, we'll explore the SOLIDWORKS host file block fix, a common problem that affects many users. We'll provide a step-by-step guide on how to resolve the issue and get your SOLIDWORKS software up and running smoothly. The Windows hosts file is a critical system

What is a Host File?

A host file is a text file used by the operating system to map hostnames to IP addresses. It's a crucial file that helps your computer communicate with other devices on a network. The host file is usually located in the C:\Windows\System32\drivers\etc directory on Windows systems.

What Causes a Host File Block in SOLIDWORKS?

When you install SOLIDWORKS, it may create entries in the host file to facilitate communication between the software and the license server. However, sometimes these entries can become corrupted or blocked, causing issues with the software. Here are some common reasons that can lead to a host file block:

  1. Corrupted or incorrect entries: If the entries in the host file are incorrect or corrupted, SOLIDWORKS may not be able to read them properly, leading to a block.
  2. Antivirus software interference: Some antivirus software may flag the host file as a potential threat and block it, causing issues with SOLIDWORKS.
  3. System configuration changes: Changes to the system configuration, such as updates to the network settings or changes to the license server, can cause the host file to become outdated.

Symptoms of a Host File Block

If you're experiencing any of the following symptoms, it's possible that your host file is blocked:

  1. Error messages: You see error messages indicating that SOLIDWORKS is unable to connect to the license server or access certain features.
  2. License server issues: You're experiencing issues with the license server, such as being unable to activate or deactivate licenses.
  3. Feature access issues: You're unable to access certain features or tools within SOLIDWORKS.

SOLIDWORKS Host File Block Fix: Step-by-Step Guide

To fix the host file block, follow these steps:

Method 1: Manually Editing the Host File

  1. Open the host file: Open the host file in a text editor, such as Notepad, with administrator privileges. To do this, right-click on Notepad and select "Run as administrator."
  2. Locate the SOLIDWORKS entries: Look for entries related to SOLIDWORKS, such as 127.0.0.1 localhost or ::1 localhost. These entries may be at the bottom of the file.
  3. Delete the SOLIDWORKS entries: Delete any entries related to SOLIDWORKS.
  4. Save the file: Save the file and close it.

Method 2: Using the SOLIDWORKS License Server Tool

  1. Download the License Server Tool: Download the SOLIDWORKS License Server Tool from the Dassault Systèmes website.
  2. Run the tool: Run the tool and select the "Fix Hosts File" option.
  3. Follow the prompts: Follow the prompts to fix the host file.

Method 3: Resetting the Host File

  1. Rename the host file: Rename the host file to hosts.old.
  2. Create a new host file: Create a new host file by copying the contents of the hosts.sample file (usually located in the same directory as the host file).
  3. Restart SOLIDWORKS: Restart SOLIDWORKS and see if the issue is resolved.

Additional Troubleshooting Steps

If the above methods don't resolve the issue, try the following:

  1. Check antivirus software: Check your antivirus software settings to ensure that it's not blocking the host file.
  2. Check system configuration: Verify that your system configuration, including network settings and license server settings, is correct.
  3. Contact SOLIDWORKS support: Contact SOLIDWORKS support for further assistance.

Conclusion

The phrase "SolidWorks host file block fix" typically refers to two distinct scenarios: a legitimate troubleshooting step for server connectivity and a common step found in unofficial software "crack" guides to prevent license validation. 1. Legitimate Use: Fixing PDM Server Issues

Engineers often modify the Windows hosts file as a temporary fix when a workstation cannot communicate with the SOLIDWORKS PDM or License Manager server.

The Problem: DNS latency or VPN issues prevent the computer from resolving the server's name to its IP address.

The Fix: Manually map the server's IP to its name in the hosts file (C:\Windows\System32\drivers\etc\hosts) to bypass the DNS lookup.

Pros: Restores immediate access to vault files and licenses without waiting for IT to fix DNS.

Cons: It is a short-term workaround. If the server’s IP changes, the connection will break again. 2. Unofficial Use: Blocking License Checks

In the context of software bypasses, "blocking" entries are added to the hosts file to redirect SolidWorks' communication attempts away from official activation servers.

The Process: Entries like 127.0.0.1 activation.solidworks.com are added to ensure the software cannot "phone home" to verify its license status.

Risk: Antivirus programs (like SentinelOne or Webroot) may flag these modifications or block the installer's ability to edit the file, often leading to installation failures or "invalid license" errors. Summary Comparison Legitimate PDM Fix License "Block" Fix Purpose Connect to a local server Prevent online validation Action Maps IP to Name Redirects to Localhost Success Indicator Vault/License becomes reachable Software runs without activation Key Risk Connection breaks if IP changes Security risk; may violate TOS Corrupted or incorrect entries : If the entries

How to Configure the Local HOSTS file to Resolve Server Name

SolidWorks Host File Block Fix Report

Introduction: The SolidWorks host file block fix is a solution to resolve issues related to SolidWorks being blocked by the Windows host file. This report provides a step-by-step guide on how to fix the issue.

Symptoms: Users may experience the following symptoms:

Cause: The issue is usually caused by the Windows host file (C:\Windows\System32\drivers\etc\hosts) blocking the connection to the SolidWorks license server.

Solution: To fix the issue, follow these steps:

  1. Locate the Host File: Open the Windows Explorer and navigate to C:\Windows\System32\drivers\etc.
  2. Open the Host File: Right-click on the hosts file and select "Open with" > Notepad (or any other text editor).
  3. Identify the Blocking Entry: Look for any entries related to the SolidWorks license server IP address or hostname. Typically, these entries are in the format 127.0.0.1 <license_server_name> or <license_server_ip> <license_server_name>.
  4. Remove or Comment Out the Blocking Entry: Delete or comment out (add a # at the beginning of the line) the entry that is blocking the connection to the license server.
  5. Save the Changes: Save the changes to the host file.

Example:

Before:

127.0.0.1 license-server

After:

#127.0.0.1 license-server (commented out)

or

(no entry)

Verification: After making the changes, restart SolidWorks and verify that it launches successfully and connects to the license server.

Troubleshooting Tips:

Conclusion: The SolidWorks host file block fix is a simple and effective solution to resolve issues related to SolidWorks being blocked by the Windows host file. By following the steps outlined in this report, users should be able to resolve the issue and successfully launch SolidWorks.

Part 5: Advanced Fixes (If the Simple Block Doesn't Work)

Sometimes, Dassault updates its servers, or your version of SolidWorks (2022, 2023, 2024) uses a different endpoint. Here is how to find what to block.

Step 5: Reboot

Restart your computer. SolidWorks should now look at your local machine for validation instead of the internet.

Part 3: The Manual "SolidWorks Host File Block Fix" (Step-by-Step)

This is the standard method. You will need Administrator privileges.

The Case of the "Phantom" Hosts File

Sometimes, the Hosts file looks clean, but SolidWorks still fails. Why? Windows has a secondary security layer: The LMHosts file.

How SolidWorks Uses the Hosts File (The "Crack" vs. The "Fix")

For decades, unauthorized users "cracked" SolidWorks by editing the Hosts file. They would add lines like:

127.0.0.1 licensing.solidworks.com
127.0.0.1 register.solidworks.com

This redirects the license check to your own computer (localhost). Since your computer isn't running a SolidWorks license server, the software stops dialing home. Legally, this is a violation of the End User License Agreement (EULA). Technically, it worked for a long time.