Can’t open a file on your Mac, but not sure where to start troubleshooting? From missing apps to security roadblocks, here are a few ways to crack those stubborn files open.

When No App Is Set to Open the File

Let’s say that when you double-click a file, your Mac asks what app you’d like to use instead of simply opening it. While this might seem annoying at first, it’s actually your Mac trying to help you make the right choice for handling that file type.

Right-click (or Control-click) on your file and select “Open With” to see a list of compatible apps already installed on your Mac. If you want to make this choice permanent, select “Other,” and be sure to check “Always Open With” when choosing an app.

An alternative approach is to click “Get Info” (Command+I) from the right-click menu instead. In the window that appears, look for the “Open with” section, choose your preferred app, and click “Change All.” Your Mac will now remember this choice for all files of this type.

If no installed apps can open your file, head to the Mac App Store. Search for the file extension (like “PSD” for Photoshop files) to find compatible apps. Also, try viewing the file in Preview first. While it can’t edit most file types, Preview can often at least show you what’s inside, which helps determine what app you really need.

When all else fails, you can simply search the web for the file extension. This should give you an explanation of what sort of file you have and what you need to open it.

When the Default App Won’t Open the File

Sometimes the right app is installed, and the file itself is fine, but it still won’t open. Start with the basics: force quit the app by pressing Command+Option+Esc or clicking the Apple > Force Quit, then try opening your file again. No luck? Check the App Store or app in question for updates—outdated apps can struggle with newer files, especially if they haven’t been optimized for your Mac’s operating system.

If updating doesn’t help, try reinstalling the app. Sometimes this fixes issues where app components have become corrupted. As a last resort, log in to or create a new user account on your Mac and try opening the file there—this can help identify if the problem is with your user account rather than the app itself.

Last but not least, try another app altogether. You can righ-click (or Control+click) on a file and select Open With then pick another app to open the file instead. Don’t forget to make your choice permanent if you decide to user this app going forward.

When macOS Security Blocks the File

“macOS cannot verify that this app is free from malware.” Sound familiar? This is Gatekeeper, your Mac’s security system, being cautious about unknown software. While this protection is valuable, sometimes it blocks legitimate files you know are safe.

The easiest workaround is to right-click the file and select “Open”—yes, the same action that didn’t work with a double-click. This brings up a slightly different dialog box that includes an “Open” option. If that doesn’t work, head to System Settings > Privacy & Security.

Recently blocked items often appear at the bottom of the screen with an “Open Anyway” button. For apps downloaded from identified developers, you might need to click the lock icon and enter your password to approve the exception.

Remember though—these security features exist for good reason. Only override them for files you absolutely trust. If you received the file unexpectedly or from an unknown source, it’s usually better to be safe than sorry.

That said, many free and open-source projects rely on circumventing Gatekeeper using this method since the projects are not-for-profit and cannot justify an Apple Developer license.

When All Else Fails

If nothing above works, the file itself might be the problem. Files can become corrupted during download or transfer—try downloading it again if possible. You can use Terminal’s “file” command to identify exactly what type of file you’re dealing with (just drag the file into Terminal after typing “file ”).

Sometimes files have incorrect extensions, and knowing the true file type can point you toward the right app.

For important files that still won’t open, check if the file has proper read permissions (Command+I, look under “Sharing & Permissions”). If permissions look wrong, try clicking the lock icon and adjusting them. You can also use Disk Utility’s First Aid feature to repair disk permissions system-wide.

Still stuck? It’s worth searching through or reaching out to community forums like Reddit. Other users might have encountered—and solved—the same issue.