Just recently I wanted to perform an antivirus scan of my Mac, so I was planning to install Malwarebytes. I downloaded the package from the official website and clicked to accept the terms and conditions. Unfortunately, for some reason the installation was stuck at the ‘Waiting for other installation to complete‘ page. While I’ve had seen this type of message before with Windows Installer, I was now working on a MacBook Pro. The installer hangs for tens of minutes, so I explored my options to unblock the installation.

Open the ‘Force Quit’ window

One of the first options you should try is to force quit the installation and try again. This should be no issue because the installation hasn’t actually started, so to interrupt it will not cause any harm whatsoever.

Force quit an app on MacOS is relatively simple an requires you to press a key combination on your keyboard: Option+Command+Escape.

Select the installer application and choose to ‘Force Quit’ it. You will be prompted with the message: ‘Do you want to force “Installer” to quit? You will lose any unsaved changes.” and here you must click ‘Force Quit’.

Manually remove the installation lock

Remove the installation lock via Terminal on your Mac has high chances of succes as well. There is a big likelihood that the previous installation has failed, but the lock was not removed. The reason could be that the previous installation failed because your Mac ran out of battery and had to shut down in the middle of the installation process. But other reasons exist as well, including an application which starts during the bootup and tries to install an app on your device.

Here are the steps to follow to manually remove the installer lock:

• Open Terminal
• Paste the following commands and press Enter: sudo rm /private/var/db/mds/system/mds.install.lock
• Reboot your computer, or enter this command instead: sudo killall -1 installd

Boot your Mac in Safe Mode

Booting your Mac in Safe Mode is your next best option. Triggering the Safe Mode option depends on your Mac: the Intel or Apple Silicon chips will have another process to follow.

Apple silicon

Intel processor

1. Shut down your Mac.
2. Turn on your Mac and continue to press and hold the power button until you see the startup options window.
3. Select your startup disk, then press and hold the Shift key while clicking “Continue in Safe Mode.”
4. Log in to your Mac. You might be asked to log in again.

1. Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.
2. Release the key when you see the login window, then log in to your Mac. 
3. You might be asked to log in again. On either the first or second login window, you should see ”Safe Boot” in the upper-right corner of the window.