Written by
Yvonne Feng
Summary: This post is about how to fix the prohibitory symbol when Mac installs the app and a prohibitory symbol on the app. It also tells you the meaning of prohibitory symbols and how to use iBoysoft DiskGeeker for Mac to clean up disk space to avoid installation issues caused by insufficient disk space.
Does the Mac show a prohibitory symbol when you install an app on it? Take it easy. Many Mac users have encountered the same problem when they install apps.
In fact, it's often caused by common reasons, so it is fixable. Let's first look at how to solve the Mac shows prohibitory symbol when installing an app issue!
How to fix Mac to show a prohibitory symbol when installing an app?
The prohibitory symbol may appear when attempting to install an app due to insufficient permissions, incompatibility of the installer with the current macOS version, or other related issues. Here are the solutions to help you fix the problem.
Share this post to help more people fix the prohibitory symbol when installing an app!
Check Disk Space
Generally speaking, installing apps requires sufficient disk space. If the space is insufficient, installation may fail, and a prohibitory symbol might appear.
You can check it by clicking the Apple menu > About This Mac > Storage to check available disk space. If the available space is less than 10GB, try to delete unnecessary files, such as large videos, photos, or downloads.
Here, we recommend using iBoysoft DiskGeeker for Mac. This professional disk management tool can quickly scan folders and large files occupying your disk space, allowing you to clean them up selectively with ease.
In addition to common junk files, it can also identify and remove hidden junk such as cache files, log files, and installation packages. Therefore, using it to clean up your Mac before downloading applications can effectively prevent download issues caused by insufficient storage space.
Verify App Compatibility
Starting from macOS Catalina, Apple no longer supports 32-bit applications. If you try to install an incompatible app, the system may display a prohibitory symbol. So, check the app's official website to confirm it supports your macOS version.
Then, open About This Mac to find your macOS version. If it's an older app, download the latest compatible version. However, if the app is no longer updated, consider finding an alternative app.
Adjust Security Settings
macOS's security mechanism (Gatekeeper) may block apps from unverified developers. Try the following steps to fix it.
- Open System Settings > Privacy & Security > Security.
- Under “Allow apps downloaded from,” select App Store and identified developers.
- If you see a message like “This app has been blocked,” click Open Anyway or Allow Anyway at the bottom of the page.
- Try installing the app again.
Re-download the Installer
The installer file might be incomplete or corrupted during the download, causing the installation to fail.
Here is how to do it.
- Delete the previously downloaded installer file.
- Go to the developer's official website or Mac App Store and re-download it.
- Ensure your internet connection is stable and check if the developer provides a checksum (e.g., SHA256).
- Verify the downloaded file and try installing it again.
Use Terminal to Bypass Gatekeeper Restrictions
For some third-party apps, macOS may completely block the installer, requiring manual bypass.
- Open Terminal (found in Applications > Utilities).
- Temporarily disable Gatekeeper by entering the following command.sudo spctl --master-disable
- Enter your admin password and press Enter.
- Try installing the app again.
- After installation, re-enable Gatekeeper for security by running:sudo spctl --master-enable
How to fix the prohibitory symbol on the app?
The prohibitory symbol on the app often indicates that macOS cannot start or run the application. This could be because macOS is blocking the application due to insufficient permissions. For example, the application's files or folders may not have the correct read and write permissions, or the system may determine that the user does not have the necessary privileges to open the app.
To resolve the prohibitory symbol issue on an app, you can first check the app's permissions. If macOS detects that the app lacks sufficient read and write permissions, it may prevent the app from launching. You can right-click the app icon, select "Get Info," and ensure that the necessary permissions are granted to the app.
Additionally, it is important to ensure that the app is compatible with your current macOS version. As macOS is frequently updated, some apps may no longer be supported or need to be updated to function properly. If the issue is due to an outdated version of the app, you can check the app's official website or the Mac App Store for any available updates.
If the above methods do not resolve the issue, you can try reinstalling the app. Reinstalling the app may help fix issues caused by corrupted files leading to the prohibitory symbol. If the problem persists, it is recommended to use an alternative app that is fully compatible with your current macOS version.
Share with your friends to help them fix the prohibitory symbol on the app!
Why is an app not installed on my Mac?
There are several reasons why an app may not install on your Mac. First, if there is insufficient disk space, the installation may fail. So, it is important to check your storage and ensure enough available space for installation. For this, you can download iBoysoft DiskGeeker for Mac and have a try!
Another common reason is permission settings. If macOS detects that the app lacks the necessary read and write permissions, it may prevent the installation. You can check and adjust file permissions to ensure the app can be installed correctly. Furthermore, the installer file itself may be corrupted or incomplete, and re-downloading it and attempting the installation again might help.
If none of the above methods solve the problem, it is recommended that you check your system's security settings to ensure that the application comes from a trusted developer and meets MacOS's security requirements.
Share this article if you find it helpful!
