I get an error message that says:

Warning. The following disk images couldn't be opened.
Image Reason SurveillanceClient.dmg invalid checksum

Does anyone have ideas on how to install this file?

  • 1
    You need to check that the download has not corrupted the file - a good site should have a checksum allowing you to check this
    – mmmmmm
    Mar 22 '16 at 21:47

In this YouTube video, they teach you how to fix this. Anyway, after El Capitan, Disk Utility has been completely changed, so now, in order to disable the checksum verification, you can just open a Terminal window and type:

defaults write com.apple.frameworks.diskimages skip-verify -bool true

Then open again your .dmg. Now it should work.

  • 1
    But you should not disable the checksum check - without knowing why it was corrupted first - do you want a Trojan?
    – mmmmmm
    Mar 22 '16 at 21:52
  • Ok i got the file to mount and the installation to open but at the end of the install it says Instillation Failed , the Installer encountered an error that caused the installation to fail. Contact software manufacturer for assistance. I contacted them and they swear it's apples fault. Any ideas? Mar 22 '16 at 22:18
  • Open Disc Utility > Images > Verify > Select your .dmg file. What's the result of this operation?
    – mgiordi
    Mar 22 '16 at 22:21
  • Operation failed with status 116 Mar 22 '16 at 22:36

I was getting this error in High Sierra and it had been bugging me for a while.

So I investigated the volumes I had mounted using Disk Utility and found that there were two uninitialized volumes remaining that I couldn't format, mount or erase.

What solved the problem for me, was clicking the Apple symbol in the upper-right hand corner and searching for 'Force Quit'. I relaunched Finder and logged out immediately, not re-opening any applications...

Then I logged back in after I had been logged out and clicked Finder > Applications > Utilities && finally I opened the 'Terminal' application.


Once in Terminal, I typed the following:

sudo chmod 775 /Volumes

typed in my password, and mounted my disk image!


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