MST File Extension

What is MST file?

Files with MST extension, also known as transformation files, are used by Microsoft Windows operating system for storing Microsoft Windows Installer ( msiexec.exe ) application installation settings. MST files contain installation configuration and parameters for a Windows application.

The purpose of MST files

The main Uses of MST is to customize Windows Installer settings whn istalling various applications on the disk. Contents of MST file are changed each time the preferred installation settings for given applications are modified.

Where are MST file used?

MST files are commonly used by programmers during software development, software version testing, and other proceses.

MST files included in MSI packages

MST files are typically included in a complete installation package, usually a MSI archive. MST transformation files allow users to change local installation settings without modifying the Windows Installer package. Appropriate settings can be included in the package by using the following syntax:

msiexec installpkg.msi TRANSFORMS= transforms.mst

Programs which support MST file extension

Programs that can handle MST files are as follows. Files with MST extension, just like any other file formats, can be found on any operating system. The files in question may be transferred to other devices, be it mobile or stationary, yet not all systems may be capable of properly handling such files.

Updated: 09/13/2022

How to open file with MST extension?

There can be multiple causes why you have problems with opening MST files on given system. What is important, all common issues related to files with MST extension can be resolved by the users themselves. The process is quick and doesn’t involve an IT expert. The list below will guide you through the process of addressing the encountered problem.

Step 1. Download and install Windows Installer

The main and most frequent cause precluding users form opening MST files is that no program that can handle MST files is installed on user’s system. This one is an easy one. Select Windows Installer or one of the recommended programs (for example, Microsoft Windows, MST File Viewer, Windows Installer XML) and download it from appropriate source and install on your system. The full list of programs grouped by operating systems can be found above. If you want to download Windows Installer installer in the most secured manner, we suggest you visit Microsoft Corporation website and download from their official repositories.

Step 2. Update Windows Installer to the latest version

If you already have Windows Installer installed on your systems and MST files are still not opened properly, check if you have the latest version of the software. It may also happen that software creators by updating their applications add compatibility with other, newer file formats. The reason that Windows Installer cannot handle files with MST may be that the software is outdated. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using Windows Installer.

Step 3. Set the default application to open MST files to Windows Installer

After installing Windows Installer (the most recent version) make sure that it is set as the default application to open MST files. The method is quite simple and varies little across operating systems.

The procedure to change the default program in Windows

• Clicking the MST with right mouse button will bring a menu from which you should select the Open with option
• Select Choose another app → More apps
• Finally select Look for another app on this PC, point to the folder where Windows Installer is installed, check the Always use this app to open MST files box and conform your selection by clicking OK button

The procedure to change the default program in Mac OS

• From the drop-down menu, accessed by clicking the file with MST extension, select Information
• Proceed to the Open with section. If its closed, click the title to access available options
• From the list choose the appropriate program and confirm by clicking Change for all....
• If you followed the previous steps a message should appear: This change will be applied to all files with MST extension. Next, click the Continue button to finalize the process.

Step 4. Ensure that the MST file is complete and free of errors

If you followed the instructions form the previous steps yet the issue is still not solved, you should verify the MST file in question. Problems with opening the file may arise due to various reasons.

1. The MST may be infected with malware – make sure to scan it with an antivirus tool.

If the MST is indeed infected, it is possible that the malware is blocking it from opening. It is advised to scan the system for viruses and malware as soon as possible or use an online antivirus scanner. If the MST file is indeed infected follow the instructions below.

2. Verify that the MST file’s structure is intact

If the MST file was sent to you by someone else, ask this person to resend the file to you. During the copy process of the file errors may occurred rendering the file incomplete or corrupted. This could be the source of encountered problems with the file. When downloading the file with MST extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.

3. Verify whether your account has administrative rights

Some files require elevated access rights to open them. Log out of your current account and log in to an account with sufficient access privileges. Then open the Windows Installer Setup Transform Format file.

4. Verify that your device fulfills the requirements to be able to open Windows Installer

If the system is under havy load, it may not be able to handle the program that you use to open files with MST extension. In this case close the other applications.

5. Check if you have the latest updates to the operating system and drivers

Latest versions of programs and drivers may help you solve problems with Windows Installer Setup Transform Format files and ensure security of your device and operating system. It is possible that one of the available system or driver updates may solve the problems with MST files affecting older versions of given software.

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