One Thing You Should Check Before Opening Any Application File
It’s easy to assume that the files we download and install on our computers are exactly what they say they are. After all, an app with a quality icon and the right name looks legit: why not ? Malware and malware developers thrive on such assumptions because the goal is for you to open these malware without question. Luckily, there’s an easy way to find out the type of any given app, program, or file on your Mac or PC—it’s just not enabled by default.
Both macOS and Windows have an option that shows the file extension for any file on your computer next to its name. Final Cut Pro.app is displayed instead of Final Cut Pro. Instead of Elden Ring, Elden Ring.exe is displayed. This is displayed for every file on your computer, which some users may not like. Not revealing file types is an aesthetic choice, and I understand it’s much cleaner to browse through all your apps and files on your PC without those 3- or 4-letter extensions at the end. I’ll cover a way to show the true file extension at will for those who prefer to keep things neat.
However, enabling file extensions all the time can be a lifesaver (from a computational point of view). Windows malware is often written as an executable file, a basic type of file that tells the computer to perform a task or series of tasks. This file extension appears as .exe, but you won’t recognize it unless you have View File Extensions enabled. Malware developers are aware of this and write their malware accordingly. The malicious file may appear on your computer as thedarkknight.mov, but reveal its full name and you will find that it is actually called thedarkknight.mov.exe. Not so innocent.
This does not mean that all types of .exe files are malicious. Far from it, .exe is a common and legitimate file type used all the time in Windows. You may have noticed in my example a few paragraphs above that a game like Elden Ring would appear as an .exe file, and that’s to be expected. It’s not about fearing every .exe you find: rather, it’s about being able to tell when a file that shouldn’t be an .exe shows up as one. Remember: if a file or application you downloaded from the Internet or as an attachment to a message appears to be sketchy, be careful not to open it.
This setting can be useful in other ways too: sometimes it’s important to know what specific file type you’re working with, especially when it comes to compatibility. For example, there are many different types of image files, and you won’t be able to tell which one is in front of you just by knowing you have a photo. This image can be in .jpeg, .pdf or .heif format: you’ll know right away if your computer tells you to.
How to show file extensions in Windows
Luckily, it’s not hard to turn on the option to view file extensions in both Windows 10 and 11. In Windows 10, open File Explorer, select View, then click the tab next to File Name Extensions. In Windows 11, open File Explorer, select View, then Show, then select File Name Extensions from the list.
You don’t need to show extensions for all files on your computer to stay safe, however, if you prefer to keep things clean and check files on a case-by-case basis, here’s how to do it: Right-click a file. , select Properties, then check its extension next to Type.
How to show file extensions on Mac
While you won’t encounter .exe files on a Mac (at least you won’t be able to run any of them), it can still be useful to show file extensions. In the end, the same principles apply: you don’t want to open an application or file with a completely different extension than you expect, and it can be helpful to know exactly what type of file you’re currently working with.
To display file extensions on macOS, open Finder, then press Command + to open Preferences (or choose Finder from the menu bar, then choose Preferences). In the Preferences window, select the Advanced tab, then select the Show all file name extensions check box.
If you’d rather check the extension for a single file rather than showing all file extensions by default, you can right-click on the file and select “Get Info”. The true file extension will be listed next to View.