No Mountable Systems Dmg Fix Free

After downloading the dropboxinstaller.dmg from the website I recieve a warning dialogue box stating the disk image could not be openend because of no mountable file system. I downloaded it several times with the same result. The firewall is turned off. I rebooted the iMac Pro. Running MacOS Mojave. Manual Steps to Fix No Mountable File Systems. In order to fix this very problem, try to mount the file using the hdiuti command from the command line. Users can also run the command on the command line as root: $ sudo hdituil attach file name.dmg. After that remove the.dmg extension and in that place use the disk image file name.

I'm trying to do a complete backup of my wife's MB from my MBP. I booted the MB into Firewire Target Disk Mode, then used Disk Utility on my MBP to make a DMG of it onto another external FW drive. Here's the log from Disk Util:

Dmg No Mountable File Systems

No Mountable File Systems Dmg Mac Fix

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:

No Mountable File Systems Dmg Fix

1. 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.)

2. 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.

3. 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.

4. 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 error 112, 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:

5. 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.

6. 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.

7. 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.