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--- title: Microsoft Threat Modeling Tool release 7.3.51110.1 - Azure description: Documenting the release notes for the threat modeling tool release 7.3.51110.1. author: nishegde ms.author: nishegde ms.service: security ms.topic: article ms.date: 11/10/2025 --- # Threat Modeling Tool update release 7.3.51110.1 - 11/10/2025 Version 7.3.51110 of the Microsoft Threat Modeling Tool (TMT) was released on November 10 2025 and contains the following changes: - Added a new safeguard that prevents users from saving `.tm7` and `.tb7` threat model files in the application's installation directory. - When attempting to save files in the install directory, the tool now prompts users to select an alternative location, such as the user's Documents folder. - The application remains open until the files are successfully moved out of Threat Modeling Tool's installation directory. - This change was introduced to prevent accidental data loss after application updates when files are stored in the application directory. This ensures threat models are saved in user-accessible locations. - Bug fixes - Accessibility fixes ## Known issues ### Errors related to `TMT7.application` file deserialization #### Issue Some customers have reported receiving the following error message when downloading the Threat Modeling Tool: ``` The threat model file '$PATH\TMT7.application' could not be deserialized. File is not an actual threat model or the threat model may be corrupted. ``` This error occurs because some browsers don't natively support ClickOnce installation. In those cases, the ClickOnce application file is downloaded to the user's hard drive. #### Workaround This error will continue to appear if the Threat Modeling Tool is launched by double-clicking on the `TMT7.application` file. However, after bypassing the error the tool functions normally. Rather than launching the Threat Modeling Tool by double-clicking the `TMT7.application` file, users should utilize shortcuts created in the Windows Menu during the installation to start the Threat Modeling Tool. ## System requirements - Supported Operating Systems - [Microsoft Windows 10 Anniversary Update](https://blogs.windows.com/windowsexperience/2016/08/02/how-to-get-the-windows-10-anniversary-update/#HTkoK5Zdv0g2F2Zq.97) or later - .NET Version Required - [.NET 4.7.1](https://go.microsoft.com/fwlink/?LinkId=863262) or later - Other Requirements - An Internet connection is required to receive updates to the tool and templates. ## Documentation and feedback - Documentation for the Threat Modeling Tool is located on [docs.microsoft.com](./threat-modeling-tool.md), and includes information [about using the tool](./threat-modeling-tool-getting-started.md). ## Next steps Download the latest version of the [Microsoft Threat Modeling Tool](https://aka.ms/threatmodelingtool).