'The following disk images couldn't be opened' Error
Mac users have noticed that the installers for the software they use is not using the extension '.exe' or '.msi' like on Windows – instead, it usually comes in a '.dmg' format. DMG, or Apple Disk Image, is a type of ISO file, which works as an installer for Mac-compatible applications. Nearly every app you download for your Mac will use this format. Sometimes, however, you may not be able to install a new piece of software because of the 'The following disk images couldn't be opened' Error. Typically, you can download the file again to see if this fixes the issue, but this solution may not always work. If you are experiencing the same issue, then you can use the following troubleshooting tips to try and resolve the problem:
Verify the Disk Image
If re-downloading the file does not help, then you should try to run your Mac's Disk Utility – it might be able to help. Head to Applications -> Utilities -> Disk Utility. Then, select the Images tab and click Verify. Finally, select the image that is causing you problem, and click Verify again. Wait for the process to finish, and try running the file again.
Look for another Source
While this is very unlikely, it is possible that the website you are trying to download the DMG file from has uploaded a corrupted or damaged disk image. This means that no matter what you do, it just will not work. Depending on the installer or updater causing the problem, you might be able to fetch a copy from a 3rd-party website. Of course, make sure to only download from credible sources to minimize the chances of encountering malicious software. While doing so, you might also want to keep your system protected by a reputable Mac antivirus tool for extra safety.