Fix: macOS Can't Open App - Complete Troubleshooting Guide

When installing apps from outside the App Store on Mac, you may encounter various security warnings that prevent the app from opening. This is macOS's security feature (Gatekeeper) in action. This guide will walk you through all common solutions.

Issue 1: "Cannot open because the developer cannot be verified"

Symptoms

When trying to open the app, you see a dialog saying:

"XXX" cannot be opened because Apple cannot verify it is free from malware.

Or:

"XXX" can't be opened because Apple cannot verify the developer.

Solutions

Method 1: Right-click to Open (Recommended for Beginners)

1. Locate the app in Finder
2. Hold the Control key and click the app icon (or right-click)
3. Select "Open" from the context menu
4. Click "Open" again in the confirmation dialog

You only need to do this once. The app will open normally afterward.

Method 2: Enable "Allow apps from Anywhere"

If Method 1 doesn't work, you can enable the "Anywhere" option in security settings:

1. Open the Terminal app
   • Press Command + Space, type Terminal, press Enter
2. Enter the following command and press Enter:

sudo spctl --master-disable

3. Enter your Mac login password (characters won't appear as you type), press Enter
4. Go to System Settings > Privacy & Security > Security
5. Under "Allow apps downloaded from", select "Anywhere"

⚠️ Security Notice: After enabling this option, only download software from trusted sources. You can run sudo spctl --master-enable to restore the default security settings when done.

Issue 2: "App is damaged and can't be opened. You should move it to the Trash."

Symptoms

After installing the app to the Applications folder, double-clicking shows:

"XXX" is damaged and can't be opened. You should move it to the Trash.

Or:

You should eject the disk image.

Root Cause

The app isn't actually damaged. macOS's quarantine attribute marks files downloaded from the internet, preventing them from running as a security measure.

Solution

1. Open the Terminal app
2. Enter the following command:

sudo xattr -r -d com.apple.quarantine /Applications/HandyMote.app

💡 Tip: If HandyMote is not in the default location:

• Type sudo xattr -r -d com.apple.quarantine (note the trailing space)
• Drag and drop the app icon into the Terminal window (the path will auto-fill)
• Press Enter to execute

3. Enter your Mac password (characters won't show), press Enter
4. Try opening HandyMote again

For macOS Ventura/Sonoma Users

On macOS 13 Ventura or later, if the error persists after running the command:

1. After executing the xattr command
2. Right-click on the app
3. Select "Open"
4. Click "Open" again in the popup dialog

Issue 3: Accessibility Permission (Required for HandyMote)

Why is this required?

HandyMote needs to control mouse movements and keyboard input, which requires the system's Accessibility permission.

How to Grant Permission

1. Open System Settings
2. Go to Privacy & Security > Accessibility
3. Click the 🔒 lock icon at the bottom left to unlock settings
4. Find HandyMote in the app list
5. Toggle the switch next to HandyMote to enable it

⚠️ Important: Without this permission, you can connect your phone successfully, but mouse and keyboard controls will not work.

Frequently Asked Questions

Q: I get "Operation not permitted" after running the command

Make sure you're using an administrator account and that you included the sudo prefix correctly.

Q: I can't find the "Anywhere" option

On newer macOS versions, this option is hidden by default. It will appear after running the sudo spctl --master-disable command.

Q: Do I need to repeat these steps after each app update?

Yes, when HandyMote is updated, the quarantine attribute may be reapplied, requiring you to run the xattr command again.

Quick Reference

If none of these solutions work for you, please contact us for assistance.