Oct 20, 2014 Mac OS X - How to disable the disk image verification You can skip disk image verification (checksum) to speed up the mounting of disk on Mac OS X (though it is not recommended). To disable this feature: Open a terminal and type the following command:% defaults write com.apple.frameworks.diskimages skip-verify YES. Oct 08, 2017 Apple took it upon themselves to break the Disk Utility in every conceivable manner. Including the preferences section that has allowed me to disable verifying the checksum of every DMG file I open. It's a pet peeve of mine to have to wait for that to complete before it opens a DMG file for an. Jan 28, 2009 I’ve been using OS X for a while now, and one thing that really irks me, especially on larger DMG files like a Leopard image, is that OS X automatically tries to verify the checksum of the DMG image file, which could take hours.
How To Skip Dmg Verification Mac Free
November 8, 2019 at 6:30 AM
Categories: macOS | View Comments
Mac Dmg Download
I ran into an interesting macOS error while working with a customer a couple of weeks ago. I didn't find a lot of good search results addressing the issue, so I decided to write up a post about it myself.
The error was as the screenshot above shows; trying to open a dmg (disk image), macOS showed the error 'no mountable file systems'. If you see the 'no mountable file systems error' while opening a dmg, here's what you should try:
How To Skip Dmg Verification Mac Free
In most cases, the downloaded dmg file is actually corrupt or had an error downloading. If possible, try downloading the dmg again, turning off any download assistant plug-ins you may have. You can try downloading the file in a different browser as well. Or if you don't need to be logged in to the site to download the file and you want to be fancy, you can try
curl -O url
in Terminal to download the file. (There's an example of that in my screenshot below.)Reboot your Mac if you haven't already tried that. Apparently there is an issue sometimes after opening too many dmg files, that is fixed with a reboot.
Try mounting the DMG on the command line in Terminal. We will at least get some sort of useful error message to go on if it still fails:
Open Terminal: In Spotlight, the search magnifying glass at the upper right corner of your screen, search for Terminal, and press enter to open the Terminal app.
Type
hdiutil attach -verbose
into the terminal. Add a space at the end, but don't press enter yet.Drag the dmg file from your Finder window onto the Terminal window and let go. This will fill in the location of the dmg file into your Terminal window.
- Press enter.
macOS Sierra (10.12) and earlier is not able to mount the new Apple File System (APFS). So if you're on macOS Sierra (10.12) or earlier and you ran hdiutil and see references to
Apple_APFS
or error112
, the issue is likely legitimate incompatibility, and this disk image won't open on this Mac without an update to the operating system.Here's an example of the end of
hdiutil attach -verbose
output that shows an APFS error due to an older version of macOS:Think about if you have any kind of security policies on this machine to prevent writing to external drives (thumb drives, optical drives, etc). I haven't seen this one in action, but I read about this being a possibility while researching the issue.
Another suggestion added by a reader (thank you, Markus!) is that filesystem errors on your main Mac drive could be the cause of the disk image mounting errors. Here are instructions from Apple for scanning and repairing errors using Disk Utility. Note that in order to scan and repair errors on your main Macintosh HD drive, you'll need to reboot your Mac into recovery mode. You'll want to choose Disk Utility in the utilities listed in the recovery mode menu.
A new discovery from a reader (thank you, Colby!) is that APFS DMGs won't mount if you're booted in macOS booted in Safe Mode. (Who knew!?!) If you're not sure if you're in safe mode, select the Apple menu > About This Mac > System Report button, then select the 'Software' heading from the left column. To exit safe mode, restart your Mac, without holding Shift during startup. Or, if you previously set your Mac to always boot into safe mode using
nvram
, turn off safe mode and have your Mac boot normally on the terminal:Open Terminal: In Spotlight, the search magnifying glass at the upper right corner of your screen, search for Terminal, and press enter to open the Terminal app.
Type/paste
sudo nvram boot-args='
and press enter.Restart your Mac.