ExplainerSoftware Installation
EXE, MSI, DMG, PKG and APK files explained
What the file endings .exe, .msi, .dmg, .pkg and .apk mean, which system each belongs to, and how to open or install them safely.
- Any device
When you download a program, the file ends in a short code such as .exe or .dmg. That ending tells you which kind of computer or phone the file is for and how to use it. The five you meet most often are explained here.
The core idea
Each system has its own way of packaging software. A file made for one system will not run on another. The ending after the last dot in the file name (the file extension) shows which system the file is for. If Windows hides extensions, open File Explorer, select View, then turn on File name extensions. In Windows 11 it is under View > Show; in Windows 10 it is a checkbox on the View tab.
Text version of this diagram
- Windows: .exe programs and .msi installer packages
- Mac: .dmg disk images and .pkg installer packages
- Android: .apk app packages, normally via Google Play
The five file types
| Ending | System | What it is | What you do |
|---|---|---|---|
| .exe | Windows | An executable file: a program, or the installer program for a larger one | Double-click it and follow the screens |
| .msi | Windows | A Windows Installer package: a set of instructions Windows follows to install a program | Double-click it and follow the screens |
| .dmg | Mac | A disk image: a virtual disk that opens like a drive and holds an app | Open it, then drag the app to Applications |
| .pkg | Mac | An installer package that places files where they belong | Open it and follow the installer |
| .apk | Android | An Android app package | Normally you never handle it: Google Play installs apps for you |
EXE and MSI on Windows
A .exe file runs code on your computer. That is why it matters where it came from. Many downloads are an .exe installer that sets up the real program. An .msi file is a more standard package, often used by businesses. For a home user, the steps are the same: double-click, approve the prompt and follow the screens. Windows asks Do you want to allow this app to make changes to your device? because installing changes the system. Select Yes only for a file you chose to download.
DMG and PKG on a Mac
A .dmg file appears as a new disk on your desktop or in the Finder sidebar. Google's instructions for Chrome on a Mac are typical: open the file, drag the app to the Applications folder, then eject the disk image in the Finder sidebar. Mozilla warns against opening Firefox directly from the disk image, because that can lose data and settings. A .pkg file works like a Windows installer: you open it and it walks you through the steps.
APK on Android
Apps from Google Play are installed for you, so you rarely see an APK file. If a website offers you an APK, you are installing outside Google Play. Google warns that if you download apps from unknown sources, your device and personal information can be at risk.
Treat an APK from a website with care
Install an APK only if you trust the maker and got the file from their official site. Never install one because a message, pop-up or caller told you to. Menu names vary by maker, so search Settings for unknown apps to see which apps are allowed to install files. Turn the permission off again afterward.
What these files do not tell you
The ending shows the kind of file, not whether it is safe. A harmful program can be an .exe, and so can a real one. What makes a download trustworthy is its source and its publisher. On a Mac, Apple says Gatekeeper checks the developer's signature and that the software has not been altered, and requires notarization by default in macOS Catalina and later. On Windows, the prompt shows the publisher name. See how to install software safely for the full routine.
Other types you may see
A .zip file is a folder of compressed files, not an installer. Open it and look inside. A document that is really an .exe is a warning sign, for example invoice.pdf.exe.
What this means for you
- Check that the file ending matches your device. A Windows
.exewill not run on a Mac or a phone. - Within one system, the version also matters. See 32-bit, 64-bit or ARM: which version do I need?
- If Windows shows a blue warning screen, read the SmartScreen warning guide.
- For a worked example, see how to install a web browser.
Frequently asked questions
Can I open an EXE file on a Mac or a phone?
No. An EXE file is built for Windows. Look for the Mac or Android version of the program instead.
Should I delete the installer after installing?
Yes, once the program works. The installer is no longer needed. On a Mac, also eject the disk image after copying the app.
What is the difference between EXE and MSI?
Both can install Windows software. An EXE is a program that can do anything its maker wrote. An MSI follows the standard Windows Installer instructions. You use them the same way.
Why does my browser warn about a download?
Browsers warn about file types that can run code. The warning is a reason to check where the file came from, not a reason to ignore it.
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Official resources used
Pages consulted while preparing this guide. Check them for the latest details.
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