Getting Started

1. Download – Sign up for a trial evaluation or purchase a license to receive an email containing a link to download PyroSim. More Help…

Where is the 32-bit version of PyroSim?

Recent versions of PyroSim do not offer a 32-bit version. NIST has focused development of FDS on 64-bit systems and 32-bit is no longer supported. Older versions of PyroSim which are compatible with 32-bit systems are available when selecting a download.

2. Install – Open the installer file (*.msi) and proceed through the installation wizard. Run the software from the Windows Start menu. More Help…

How will I know when to install a new version?

PyroSim will now automatically notify you when it is time to upgrade to a new version. If you turn off automatic updates or want to check at any time, you can click Check for Updates on the Help menu.

How do I install the floating license manager?

All instructions related to floating licenses are found in the Installation Guide which is linked in your purchase confirmation email.

3. Activate – For node-locked licenses, input the activation key from your email in the Licensing and Activation window. For floating licenses, there are some extra steps that must be taken for a license file to be created (please click the following link for more detail). More Help…

How do I activate a floating license?

  1. Install Thunderhead License Manager onto the computer that will act as the license server. This can be any computer on the local network, including a computer running PyroSim. You can download the latest version of the License Manager and PyroSim from this web page.
  2. Follow the Installation Guide that is also available on the downloads page, in the same area as the license manager installation program.
  3. Provide the “HostID” and “Hostname” that is provided in one of the steps of the installation process.
Once we have this information, we can create the license file and send it back to complete the License Manager activation process.

How do I move my license to a new computer?

To begin the process, please fill out and return a PyroSim and/or Pathfinder license transfer request document to Once this is received, Thunderhead Engineering will associate the license keys to the new host information and send you a new license file.

How do I reactivate after reformatting my computer or changing hardware components?

Either of these actions will affect the computer identification information and it is therefore the same as transferring a license to a new computer.

Why do I receive License Copy Error “Could not copy license file to Local License folder.”?

The “Application Data” folder must be properly junctioned to the C:ProgramData folder. Test and fix your Application Data junction with the following instructions:

  1. To open a shell window, type cmd.exe in the Windows “search” box
  2. To navigate to the ProgramData folder, type the following and press enter. cd C:ProgramData and press enter
  3. To list junction points in the directory, enter the following text. dir /aL
  4. You should see “Application Data” in this list. If it’s missing, you can remove any bad junction, and create the good one with the following two commands. rmdir "Application Data" mklink /j "Application Data" C:ProgramData

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