Locklizard Installation Instructions & Troubleshooting

Some downloads sold by TMS are protected by Locklizard DRM and can only be opened using the Locklizard Viewer. Protected products are clearly noted on the store page and can also be identified by a SKU beginning with LLF. These products are provided as .PDC files, which cannot be opened using any other PDF software.

Locklizard products sold by TMS provide single-user access only. Visit these vendors to see multi-user options.

Help Center

See the links below for help with common issues. Contact TMS for additional help with licenses, printing, or other issues.

License Information

Click here for your license information or go to your account page then click on Orders and Document License.

Locklizard Installation Instructions

Step 1. Install Locklizard

Download the Safeguard PDF Viewer installer for your operating system (use the first green button in the Product column).

Note: The instructions below apply to Windows operating systems. Additional instructions for other operating systems can be found on the download page above.

Run the installer by right-clicking on the file and selecting Run as administrator*

*Make sure that you administrator access on your system. You may also need to disable firewalls and antivirus if you’re unable to activate your license.

Step 2. Download Your Files

Open your account page and click the Orders tab to open the menu shown below.

Downloads – Download any files that you have purchased from TMS
Document License – Access your Locklizard license information

Step 3. Register Your Device

Use the License Download link found on your Document License page to save your license file to a folder where you will be able to find it. The license will be saved with a .llv file extension.

Find your license file and double-click it to register your device. A registration successful message should appear and you can now access protected files on that device.

If this message appears but you still can’t access files, disable any firewalls and antivirus then try again.

If double-clicking on the license does not register your computer, use the steps below:

  • Right click on the license file
  • Select “Open with” and click on “Locklizard Safeguard Viewer” if it appears in that list
  • If it does not appear in that list, select “Choose another app”
  • Scroll down and click “More apps” then scroll down again to select “Look for another app on this PC”
  • Navigate to the folder below, select PDCViewer64.exe, then click Open
    • C:\Program Files\Locklizard Safeguard PDF Viewer


Opening the license file does not register your computer

See Step 3 in the instructions above.

Error Message: No more licenses are available.

You have registered the maximum number of devices. Contact TMS to request additional licenses for your account.

Error Message: Cannot find DLL file.

The required .dll file may be blocked by your antivirus. Uninstall the Safeguard Viewer and reinstall with your antivirus disabled or add it to your list of trusted programs.

Error Message: Error while unpacking program.

The file was corrupted during download or by your antivirus software, you don’t have Administrator rights, or are using an unsupported OS. Try downloading the file again, temporarily disable any antivirus software, and the run the file as an administrator.

Error message: You don’t have access to this document – no access to document.

Your keystore may be corrupted — remove the keystore and register again. If the error persists, contact TMS to make sure you were given proper access and have the most updated file.

Error Message: Invalid license file. The license you are using does not match your computer details.

Remove the keystore and register again.

For additional errors, consult the Locklizard Knowledge Base