File Block Install: Solidworks Host

The SolidWorks host file block install is a powerful, legitimate tool for system administrators and professional users who understand the trade-offs. It stops unwanted telemetry, prevents "license drift" on networked machines, and can rescue an installation that refuses to validate due to a dead activation server.

The Master Checklist:

By following this guide, you take back control of your licensing stability. Remember: With great power comes great responsibility. Use the block wisely, keep your licenses legal, and your engineering workflow will remain uninterrupted for years to come.

Need further help? If you still face the "SolidWorks host file block install" error after these steps, you likely have a corrupted Windows hosts syntax. Open a command prompt and run sfc /scannow. If that fails, contact your VAR (Value Added Reseller) – but do not mention you edited the hosts file, or they will void support.

This guide is for informational purposes only. Always comply with your software licensing agreement.

If you are looking for the specific entries to add to your Windows hosts file to prevent SOLIDWORKS from communicating with license validation servers during an installation or startup, you typically use the following lines. Hosts File Entries

To block these connections, copy and paste the following text into your hosts file:

127.0.0.1 im.solidworks.com 127.0.0.1 ext-im.solidworks.com 127.0.0.1 activate.solidworks.com 127.0.0.1 ext-activate.solidworks.com 127.0.0.1 standard.solidworks.com Use code with caution. Copied to clipboard How to Edit the File Open Notepad as Administrator

: Search for "Notepad" in the Start menu, right-click it, and select Run as Administrator Navigate to the Folder File > Open and paste this path: C:\Windows\System32\drivers\etc

Note: Change the file type filter in the bottom right from "Text Documents ( .txt)" to "All Files ( )" to see the file.* Open 'hosts' : Select the file named (it has no extension). Add the Text

: Scroll to the bottom, paste the entries above on new lines, and save the file. Rackspace Technology

Blocking these hosts is often done to bypass "Checking for Updates" delays or for troubleshooting license manager connectivity in private networks. If you are experiencing an "Installation failed" error, you may also need to repair the installation through the Windows Control Panel. Are you trying to resolve a specific error code during the installation process?

Windows hosts file entries mapping SOLIDWORKS domains to 127.0.0.1 can block license activation, requiring users to remove these lines and flush the DNS cache to resolve installation issues. If issues persist, verifying Windows Firewall ports 25734 and 25735, disabling antivirus protection, or utilizing the Product Activation Wizard for email activation can bypass further restrictions. Read the full guide at Logical Solutions logicalsolutions.in How to Install SOLIDWORKS - Logical Solutions

Title: A Reliable Workaround for Installation Issues, But Not a Silver Bullet

Rating: ⭐⭐⭐⭐ (4/5)

The Bottom Line: Editing the host file to block SolidWorks server connections is a highly effective method for resolving specific installation hang-ups and "cannot connect to server" errors, particularly for standalone installations or network license issues. However, it is technically a workaround rather than an official fix, and it requires precise syntax to avoid breaking the installation entirely.

Pros:

Cons:

Detailed Experience: I utilized the host file block method during a fresh install of SolidWorks 2024 on a high-security corporate network. The standard installation manager failed repeatedly at the "Initializing" stage due to firewall restrictions blocking callbacks to swdm.solidworks.com and activation.solidworks.com.

By mapping these domains to 127.0.0.1 in the Windows etc/hosts file, the installation manager immediately skipped the online check and allowed the install to proceed from local files.

Crucial Tip for Users: If you are using this method for a Network License (SNL) setup, be extremely careful not to block your internal license server address. Only block the external SOLIDWORKS validation addresses. Additionally, remember to remove the entries from the host file after the installation is complete if you want the software to successfully validate the license upon the first launch.

Final Verdict: This is a necessary skill for any IT admin managing SolidWorks deployments in restricted environments. It is not a "fix-all" for every installation error, but for connectivity-related stalls, it works 100% of the time. Just remember to undo the changes post-install to ensure your license validation remains healthy.

Blocking SolidWorks Installation using Hosts File

The hosts file is a system file used to map hostnames to IP addresses. It can be used to block or redirect access to specific websites or servers. In this write-up, we will explore how to block the installation of SolidWorks by modifying the hosts file.

Why Block SolidWorks Installation?

There may be several reasons why you want to block the installation of SolidWorks on a computer:

Modifying the Hosts File

The hosts file is located in different directories depending on the operating system:

To block the installation of SolidWorks, you need to add entries to the hosts file that redirect the SolidWorks installation servers to a non-existent or local IP address.

SolidWorks Installation Servers

The following servers are used during the SolidWorks installation process:

Blocking SolidWorks Installation

Add the following lines to your hosts file:

127.0.0.1 install.solidworks.com
127.0.0.1 www.solidworks.com
127.0.0.1 api.solidworks.com

or

0.0.0.0 install.solidworks.com
0.0.0.0 www.solidworks.com
0.0.0.0 api.solidworks.com

Save the changes to the hosts file.

Testing the Block

To test if the SolidWorks installation is blocked, try to download and install SolidWorks. The installation process should fail or be redirected.

Reverting the Changes

If you want to allow the installation of SolidWorks, simply remove the entries you added to the hosts file.

Conclusion

Modifying the hosts file is a simple and effective way to block the installation of SolidWorks. This method can be used to control access to specific software or websites. However, it is essential to note that this method can be bypassed by using alternative installation methods or by modifying the hosts file itself.

Additional Considerations

Best Practices

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].

The phrase "SolidWorks host file block install" typically refers to two distinct technical scenarios: using the Windows hosts file to resolve server connection issues during a legitimate networked installation (such as PDM or SolidNetWork License Manager), or using it to prevent the software from "phoning home" to activation servers. 1. Using the Hosts File for Legitimate Installations

When installing SolidWorks in a professional environment, the client machine must often communicate with a license or PDM server. If your local network's DNS cannot resolve the server's name to its IP address, the installation or software launch may fail. How to Configure the Hosts File for Server Access:

Locate the File: Navigate to C:\Windows\System32\drivers\etc\.

Run as Administrator: You must open Notepad as an Administrator to save changes to this file.

Add Server Entries: Underneath any existing text, add a new line with the server's IP address, a tab or space, and then the server name (e.g., 192.168.1.100 MyPDMSever).

Refresh DNS: Open a Command Prompt and type ipconfig /flushdns to ensure Windows recognizes the manual override. 2. Blocking Connections via the Hosts File

Some users attempt to block SolidWorks from reaching its official activation or update servers by redirecting those domain names to an invalid IP address, such as 127.0.0.1 (localhost) or 0.0.0.0. This is sometimes used in unofficial installation guides to prevent the software from verifying license keys against Dassault Systèmes' databases.

Commonly Blocked Domains (Proceed with Caution):While specific "block lists" change, they often target domains like: im.solidworks.com im-ak.solidworks.com dl-ak.solidworks.com 3. Troubleshooting "Blocked" Installations

If your legitimate installation is being blocked, it may not be the hosts file at all. Common culprits include: CurrentWare How to Block Websites Using the Hosts File on Windows 10/11

Blocking specific host addresses is a common method for troubleshooting network licensing issues or preventing unwanted communication during a SOLIDWORKS installation. This is typically done by editing the Windows hosts file to redirect hostnames to a non-existent or local IP address. 1. Access the Windows Hosts File

The hosts file is a protected system file. You must use an administrator account to modify it. Open the Start Menu and type Notepad. Right-click Notepad and select Run as Administrator. In Notepad, go to File > Open.

Navigate to the following directory: C:\Windows\System32\drivers\etc\.

Change the file type filter in the bottom-right corner from "Text Documents (.txt)" to **All Files (.*)** to see the hosts file. Select the file named hosts (no extension) and click Open. 2. Add Block Entries

To "block" a hostname, you map it to 0.0.0.0 or 127.0.0.1 (the local loopback address), which prevents the computer from reaching the actual server.

Scroll to the bottom of the file, past any lines starting with #. Add a new line for each address you want to block. Format: [IP Address] [Hostname]

Example to block a specific server: 0.0.0.0 im.solidworks.com Example for local licensing: 127.0.0.1 [Your_Server_Name]. Save the file (Ctrl + S) and close Notepad. 3. Apply Changes (Flush DNS)

After saving the file, you must clear your computer's DNS cache so it recognizes the new rules immediately. Open the Command Prompt (type cmd in the Start menu).

Type the following command and press Enter:ipconfig /flushdns. 4. Troubleshooting Common Blocks

If the installation still fails or communication persists, check these common hurdles:

Antivirus Interference: Some security software (e.g., ZoneAlarm, Webroot) specifically locks the hosts file to prevent unauthorized changes. You may need to disable "Lock Hosts File" in your antivirus settings.

Read-Only Attribute: If you cannot save the file, right-click the hosts file in File Explorer, select Properties, and ensure Read-only is unchecked.

Firewall Rules: For license manager issues, blocking the host file may not be enough; you might need to create inbound/outbound rules in Windows Defender Firewall for ports 25734 and 25735.

Blank Installer Screen: If the installer window is white/blank, this is usually caused by Windows blocking HTML files in the installation media. Right-click the installation folder or setup.exe and select Unblock in the Properties menu. How to Configure the SOLIDWORKS PDM Local HOSTS file

The Strategic Use of Host File Modification in SOLIDWORKS Installations

When installing SOLIDWORKS, particularly in complex network environments or when troubleshooting licensing issues, the Windows Hosts file serves as a critical, albeit manual, intervention point. Modifying this file to block or redirect specific traffic is a common practice used by system administrators to bypass installation bottlenecks, manage license server communication, and ensure software stability. The Role of the Hosts File

The Windows Hosts file is a plain-text file that maps hostnames to IP addresses. It acts as a local "phone book" that the operating system consults before reaching out to external Domain Name System (DNS) servers. In the context of a SOLIDWORKS installation, this file can be used to:

Force License Server Connection: By mapping the server name to a specific IP, you ensure the installer finds the SolidNetWork License (SNL) Manager without relying on potentially slow or misconfigured network DNS. solidworks host file block install

Bypassing Validation Blocks: Sometimes, organizational firewalls or proxy settings interfere with the SOLIDWORKS Installation Manager's ability to verify serial numbers or download files. Adding specific block or redirect rules can occasionally stabilize these connections. Why Block or Redirect During Install?

The primary reason for "blocking" via the hosts file during a SOLIDWORKS setup is to prevent the software from attempting to phone home to a server that is causing the installation to hang.

Installation Speed: If the Installation Manager spends too much time attempting to verify a license against a non-responsive server, the process can take hours. Redirecting that hostname to a local loopback address (127.0.0.1) can force the installer to skip that check or move to the next step immediately.

Network Independence: In offline or "dark site" installations, the hosts file ensures that the software doesn't "break" when it cannot find the standard Dassault Systèmes validation servers. Risks and Best Practices

While effective, modifying the hosts file is a "brute force" method that carries risks:

Maintenance Overhead: If the IP address of your license server changes, the hardcoded entry in the hosts file will prevent SOLIDWORKS from launching until the file is manually updated.

Security Software Interference: Modern antivirus and Endpoint Detection and Response (EDR) tools often protect the hosts file from changes. Attempting to modify it during an install might trigger a security alert or cause the installation to fail entirely. Conclusion

Using a host file block or redirect is a powerful troubleshooting tool for SOLIDWORKS users. It allows for a more controlled installation environment, especially when dealing with stubborn licensing hurdles. However, it should be treated as a temporary fix or a last resort, as long-term stability is best achieved through proper DNS configuration and network firewall rules.

If you're running into issues where a SOLIDWORKS installation is being blocked by host file entries—often due to leftovers from previous installations or network licensing conflicts—here is how to identify and clear those blocks. 🚩 Why this happens

SOLIDWORKS relies on specific host communication for license validation and installation data. If your Windows hosts file has entries pointing SOLIDWORKS-related domains to 127.0.0.1 or 0.0.0.0, the Installation Manager will fail to connect. 🛠 How to fix it (Host File Cleanup)

Open Notepad as Administrator: Search for Notepad in your Start menu, right-click it, and select Run as Administrator.

Open the Hosts file: Go to File > Open and navigate to:C:\Windows\System32\drivers\etc\(Change the file type dropdown from "Text Documents" to "All Files" to see the hosts file).

Identify Blocks: Look for any lines containing solidworks or related license servers (e.g., im.solidworks.com).

Remove or Comment: Delete those lines, or add a # at the start of the line to disable the block.

Save and Flush DNS: Save the file. Then, open Command Prompt and type ipconfig /flushdns to apply the changes immediately. 🛰 Network Licensing Tip

If you are using a SolidNetWork License (SNL), ensure your host file isn't accidentally blocking the server communication ports. The default ports are 25734 and 25735. If the installation still fails, you may need to add an exception for these in your Firewall settings rather than the hosts file. 🔄 What if it's still blocked? If the host file is clean but the install won't budge:

Repair the Installation: Go to Control Panel > Programs and Features, select SOLIDWORKS, and click Change > Repair your installation.

Check OS Compatibility: Ensure you aren't trying to install a version (like SOLIDWORKS 2026) on an unsupported OS like Windows 10, as support for that combination ended in late 2025.

Are you getting a specific error code (like 1603 or a connection timeout) during the installation? Windows 10: Block ANY Website by Editing The Hosts File

🛠️ Troubleshooting: SOLIDWORKS Installation Blocked by Hosts File

If you are seeing errors like "Could not connect to the SOLIDWORKS server" or the Installation Manager hangs during the pre-check, your Windows hosts file might be blocking essential communication. Why is this happening?

The hosts file is used by Windows to map specific hostnames to IP addresses. Sometimes, security software or previous manual edits add entries that "blackhole" (redirect to 127.0.0.1) SOLIDWORKS licensing or update domains, preventing the installer from verifying your serial number. How to Fix It:

Locate the File: Open File Explorer and go to:C:\Windows\System32\drivers\etc\

Open as Admin: Right-click hosts and open it with Notepad (ensure you run Notepad as an Administrator, or you won't be able to save).

Identify Blocks: Look for any lines containing solidworks.com or im-ak.solidworks.com. Example of a blocked line: 127.0.0.1 im-ak.solidworks.com

Clean Up: Delete those lines or add a # at the beginning of the line to comment them out.

Save & Flush: Save the file. Then, open Command Prompt and type ipconfig /flushdns to clear your cache.

Pro-Tip: If the installer still fails, ensure your firewall isn't doing the same job the hosts file was doing! You can also manage background updates through the SOLIDWORKS Installation Manager to ensure everything is running smoothly.

You might have a valid license key, yet the installation fails. Here is why admins use the host file block during installation:

Cause: Windows sometimes saves the file as hosts.txt if not careful.
Solution: Verify the file has no extension (just hosts). In File Explorer, enable “File name extensions” view.

This report outlines technical issues and resolutions related to the Windows "hosts" file and file blocking during SOLIDWORKS installations.

Technical Report: SOLIDWORKS Installation & Host File Issues 1. Hosts File Intervention

The Windows hosts file (C:\Windows\System32\drivers\etc\hosts) is often a point of failure or a necessary workaround during installation and licensing.

Security Software Blocking: Antivirus programs like SentinelOne, Webroot, and ZoneAlarm frequently prevent the SOLIDWORKS launcher from writing to the hosts file.

Resolution: Users must manually uncheck "Prevent any program from modifying the HOSTs file" (Webroot) or "Lock Hosts File" (Zone Alarm) before proceeding. The SolidWorks host file block install is a

PDM Connection Workaround: If a DNS server cannot resolve the server name, technical support may advise manually adding the server IP and name to the local hosts file to bypass the lookup.

File Status: Ensure the file is not set to "Read-only" in its properties and does not have a .txt extension hidden by Windows. 2. Windows File Blocking (Blank Screen Error)

A common installation error is a "Blank Installation Manager" screen.

Cause: When installation media is downloaded as a ZIP, Windows Explorer may block specific HTML files during extraction for security.

Identification: This occurs primarily in the directory: \sldim\lang\english\HTML\. Resolution: Navigate to the \HTML\ folder.

Right-click on frameset.html (and others if necessary) and select Properties. Click the Unblock button at the bottom of the General tab. 3. Network & Firewall Restrictions

Outbound Rules: If SOLIDWORKS is unable to connect for activation, a new outbound rule may need to be created in the Windows Firewall to "Allow the connection" for the specific program executable.

3DEXPERIENCE Launcher: For modern cloud-connected versions, deleting the 3DEXPERIENCELauncher folder in C:\Programdata\DassaultSystemes\ and restarting can resolve stubborn installation hangs. 4. Summary Table of Resolutions Location/File Resolution Blank Install Screen \sldim\lang\english\HTML\frameset.html Right-click Properties -> Unblock Hosts Write Error C:\Windows\System32\drivers\etc\hosts Disable AV "Lock Hosts" setting; check Read-only status PDM Server Not Found C:\Windows\System32\drivers\etc\hosts Manually add [IP Address] [Server Name] Activation Blocked Windows Firewall Create Outbound Rule to "Allow connection"

This guide is intended for educational and technical troubleshooting contexts. It explains a common method used to prevent SolidWorks from “phoning home” to validate licenses or check for updates during a specific installation workflow.

Cause: Newer versions of SolidWorks (2022 onward) have hard-coded fallbacks that detect hosts file redirection and refuse to proceed.
Solution: You must either:

Prefer controlling access via license server configuration, firewall rules, or vendor-approved offline activation methods rather than hosts-file blocking; use hosts-file edits only as a short-term, well-documented troubleshooting measure after confirming legal and support implications.

Related search terms for further research (suggested): "SolidWorks activation servers", "SolidWorks offline activation", "hosts file block license server", "SolidWorks network license manager".

Blog Post: How to Fix SolidWorks Installation Blocks via the Hosts File

Installing SolidWorks should be straightforward, but sometimes security settings or network glitches can bring your progress to a halt. One common culprit is your computer’s hosts file, which may be blocking the installer from reaching critical activation servers or local network repositories. Why the Hosts File Matters

The Windows hosts file acts like a local phonebook, mapping hostnames to IP addresses before your computer even checks the internet. If this file contains incorrect entries or is locked by security software, the SolidWorks Installation Manager may fail to connect, leading to blank screens or "Installation Failed" errors. Step-by-Step: How to Unblock Your Install

If you suspect your hosts file is causing issues, follow these steps to clean it up or add necessary workarounds:

Open Notepad as Administrator: Search for Notepad in your Start menu, right-click it, and select Run as Administrator.

Navigate to the File: In Notepad, go to File > Open. Navigate to C:\Windows\System32\drivers\etc\. Make sure to change the file type filter from "Text Documents" to "All Files" to see the hosts file.

Check for Blocks: Look for any lines that don't start with a #. Specifically, look for entries related to "SolidWorks" or "Dassault" that might be redirecting traffic to 127.0.0.1 (localhost), which effectively blocks the connection.

Add a Server Workaround (Optional): If you are installing from a network license or PDM server and the DNS is failing, add a new line at the bottom: [Server IP Address] [TAB] [Server Name].

Save and Flush DNS: Save your changes in Notepad. Then, open a Command Prompt and type ipconfig /flushdns to ensure Windows recognizes the updates immediately. Still Blocked?

If you can’t even edit the file, your antivirus (like SentinelOne or Webroot) might be locking it. Temporarily disable your security software or check for "Host File Protection" settings to allow the modification.

If your Installation Manager still shows a blank screen even after checking the hosts file, try this quick fix for blocked HTML files:

Blocking SolidWorks via the host file is a method used to prevent the software from connecting to the SolidWorks activation servers. This is typically done to prevent the software from verifying a license online. By following this guide, you take back control