SOLIDWORKS "hosts file block" typically refers to an error where the installer or software cannot write to the Windows hosts file, often due to aggressive antivirus settings or a read-only attribute. This is also a common workaround used to resolve SOLIDWORKS PDM
connectivity issues by manually mapping server names to IP addresses to bypass DNS failures. Fix: Permission Denied or Blocking Error
If you are seeing a "permission denied" error during installation or use: Disable Antivirus Blocks : Certain security software (like SentinelOne
) has specific features that lock the hosts file to prevent hijacking.
: Uncheck "Prevent any program from modifying the HOSTs file." Zone Alarm : In Advanced Settings, uncheck "Lock Hosts File." Remove Read-Only Attribute Navigate to C:\Windows\System32\drivers\etc Right-click the file and select Properties Extension Check : Ensure the file is named exactly with no extension. It should not be How to Manually Edit the Hosts File
To fix PDM connectivity or manually bypass DNS lookups for a SOLIDWORKS server: Open 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 . Change the file type filter in the bottom right to All Files ( . Navigate to C:\Windows\System32\drivers\etc and select Add Server Mapping
: At the bottom of the file, add a new line with your server's IP address, a space, and then the server name: 192.168.1.100 MyPDMSeverName : After saving, open a Command Prompt and type ipconfig /flushdns to force Windows to recognize the changes immediately. When to Use This Fix PDM Server Resolution
: When the client machine can "ping" an IP but not the server name, indicating a DNS issue. Licensing Errors
: If the SolidNetWork License Manager cannot reach the license server due to name resolution failure. server names for your office network to complete the file edit? Retired - SOLIDWORKS Forums
Windows protects the Hosts file by default. You must be an administrator to modify it.
Locate the File: Navigate to C:\Windows\System32\drivers\etc. Modify Security: Right-click the hosts file and select Properties. Go to the Security tab and click Edit.
Select your user account and check the box for Full Control or Modify under the Microsoft Learn guide. Click Apply and OK. 2. Edit the Hosts File to Fix Blocks solidworks host file block fix
Once permissions are granted, you can remove lines that might be blocking SOLIDWORKS communication.
Open Notepad as an Administrator (Search for Notepad, right-click, and select "Run as Administrator").
In Notepad, go to File > Open and browse to C:\Windows\System32\drivers\etc. Change the file type filter to All Files (.). Open the hosts file.
Look for any entries related to solidworks.com or your internal license server IP (e.g., 127.0.0.1 license.solidworks.com).
Fix: Delete these lines or add a # at the beginning of the line to comment them out. Save the file and restart SOLIDWORKS. 3. Check Firewall Outbound Rules
If the Hosts file is clear but you still face blocks, your firewall may be preventing the connection.
Verify Rules: Ensure there isn't an Outbound Rule blocking the SOLIDWORKS executable (SLDWORKS.exe).
Configuration: As detailed in community guides, you can manage these settings via the Windows Defender Firewall with Advanced Security menu by checking the "Outbound Rules" section. 4. Quick SOLIDWORKS Fixes
If the issue is related to file corruption rather than connectivity:
Repair Function: Use the built-in SOLIDWORKS Repair Tool when prompted by a corruption dialog box.
Force Rebuild: Use Ctrl + Q to perform a deep rebuild of the entire document from the ground up.
Are you experiencing a specific License Error code (like -15 or -8) that led you to the hosts file? 11 SOLIDWORKS CTRL Key Shortcuts to Start Using Today SOLIDWORKS "hosts file block" typically refers to an
The "hosts file block" is a common fix used when SolidWorks cannot connect to its license server (Error -15, 10, 10061) or when DNS issues prevent the software from "finding" your workstation or server. 🛠️ The Direct Fix: Modifying the Hosts File
To bypass DNS translation issues and manually link an IP address to a server name, follow these steps: Open Notepad as Admin : Search for in the Start menu, right-click it, and select Run as Administrator Open the File : In Notepad, go to File > Open and navigate to: C:\Windows\System32\drivers\etc\ Change File Type : In the bottom-right corner of the "Open" window, change .txt documents to see the Add the Entry : Scroll to the very bottom and add a new line with the IP address Server Name 192.168.1.100 YourServerName Save and Flush : Save the file. Open a Command Prompt ipconfig /flushdns to force the system to recognize the change immediately. Hawk Ridge Systems ⚠️ Important: "Blocking" vs. "Unblocking" Unblocking (Legitimate Fix)
: Adding entries to the hosts file "unblocks" communication by telling your PC exactly where to look for the license server when the network fails to do so. Blocking (Cracked Software) : In unofficial versions, users often add entries like 127.0.0.1 activation.solidworks.com
to prevent the software from "calling home" to verify a license. This is a common cause for Activation Wizard Error 72 or permanent lockouts if the software detects tampering. 🔍 Additional Connectivity Troubleshooting
If the hosts file edit doesn't work, the "block" might be elsewhere:
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. Check for other blocking mechanisms:
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
Before you rush to edit system files, ensure you actually have the Hosts file block issue. Many users misdiagnose a simple firewall rule or expired subscription.
At the bottom of the file, add the following lines. Each line follows the pattern:
[IP address to redirect to] [domain name to block]
Common SolidWorks servers to block:
127.0.0.1 activation.solidworks.com
127.0.0.1 register.solidworks.com
127.0.0.1 login.solidworks.com
127.0.0.1 solidworks.com
127.0.0.1 dsxclient.3dexperience.3ds.com
127.0.0.1 lmtools.dassault-systemes.com
127.0.0.1 licensing.3ds.com
127.0.0.1 swym.3dexperience.3ds.com
127.0.0.1 customersupport.solidworks.com
127.0.0.1 api.sw.solidworks.com
💡 Pro tip: Add a comment line above to remind yourself why you did this:
# SolidWorks block list - added March 2026
