Limitations on Protected Download Products

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.

Limitations and Restrictions

Please review the restrictions below before purchasing a protected download product.

File Format

  • Protected downloads are provided in PDC format only.
  • Locklizard Safeguard Viewer is required to view PDC files. This file format is not supported by other PDF software.
  • The following operating systems are supported by Locklizard: Windows, Mac, iOS, and Android


Printing and Copying

  • Limited printing of up to 2 watermarked copies is permitted for most products (unless otherwise stated on the product page).
    • For these documents, Locklizard will allow the print button to be used twice. Each use of the print button counts against the print limit.
  • Highlighting and copying of text is not possible. However, screenshots are permitted.


  • An internet connection is required at least once every 7 days in order to perform a license validity check.
  • Orders of protected downloads are refundable for 5 business days from the time of purchase. Refer to the TMS Refund Policy for more information.
  • TMS Staff will provide limited technical support for installation and access issues. However, if after ½ hours the issue can not be resolved TMS will refund your purchase and revoke your Locklizard license.

Frequently Asked Questions

Can I print from a .PDC document?

Most TMS publications provide limited printing. These files can be printed from up to 2 times. Some files (such as Masonry Structures, Masonry Course Notes, and Plan Set) do not allow any printing. Eligible download purchases may be exchanged for printed copies in accordance with the TMS Refund Policy.

If you are having trouble printing a document, try printing in batches of 20 pages. Contact TMS to have more prints added to your account.

Can I copy text from a .PDC document?

Locklizard Safeguard Viewer does not allow highlighting or copying of text. However, screenshots are permitted.

Can I access .PDC documents offline?

Documents can be viewed offline. However, the software will require an internet connection once every 7 days to perform a license validity check.

Can this file be used to provide access to multiple users?

Locklizard cannot be used in thin client or virtual environments in order to provide access to multiple users. Licenses from TMS provide single-user access only. Multi-user options are available through these vendors.

On how many devices can the Locklizard software be installed?

Licenses from TMS can be activated on up to 2 devices. Contact TMS if you’ve replaced your computer and need additional licenses.