Cannot install OS Mac High Sierra

Mine gave the same error message. After rebooting a few times and getting to the same spot, I found a post that said to hold down the shift key (Boot into safe mode) to get past it. I did this and the progress bar froze at about 90%. I hard rebooted it after about 10 minutes of inactivity and tried it again. The second/or third time of trying to boot into safe mode finally progressed. A different looking progress bar appeared followed by the normal progress bar. After that a progress bar appeared telling me that Installation was occurring. ~40minutes later everything was installed and seems to be working fine.

I have no idea if this impacted anything, but while I was on the first screen with the original error message, I clicked the menu bar at the top and connected to my wireless network. Like I said, I have NO IDEA if this impacted anything, but it was something that I did and my system completed the installation successfully.

Click on the dialog box, not restart, and a menu bar should

come and one of the menus should have an option to chose

start up disk.

Try starting the install again and note the very first time that box

comes and what the message is. The error you state usually

happens after you press the restart and there is usually a different

one for the very first one.

I tried this many times without luck.. I think. It finally worked after I restarted and during boot I held down the Option(Alt) key and selected the install disk as the Startup disk and then it finally worked. Whether it was because of the multiple restarts or this, I do not know.

The install itself took a loooong time.

After several reboots, I went into the disk utility (clicked on the error box to get the menu up). After seeing that the volume only had 19Mb left. I brought up the menu again to open a terminal window.

This allowed me to access all volumes:

** PROCEED WITH CAUTION **

>>Make yourself aware of how to move, delete and manipulate files/folders from the volumes.

I navigated to my normal folders where I store all my files, and started to remove a lot of folders and got over 20Gb back. Exiting the terminal the machine reboots and hey pesto - the Installation Resumed.

So before you attempt a repair of the drive etc... just check the storage space available - because you might have just ran out due to the file being downloaded to install etc.

after unsuccessfully trying the safe mode solution i booted into recovery - went to disk utilities - noticed my ssd wasn't mounted - i mounted my ssd and rebooted which restored my mac to macos sierra - i reinstalled high sierra ...succesfully

Hey Smorgie. Found this thread looking to resolve the same issue. Followed all the steps to no avail... resorted to visit the apple store and spoke with a genius. Their diagnosis was my MacBook Pro was in limbo... neither installing high sierra nor keeping my old OSX... my Macintosh HD would not mount, so they basically gave me 2 options either install high sierra and lose my data or extract my data using a data recovery third party and then reinstall OSX... anyways I tinkered with it... went to disk utility...and ran first aid on the unmountable Macintosh HD...took a while but it worked... it suddenly mounted and I choose it as a start-up disk... and hey presto... currently backing up before trying the update again...BACK UP YOUR DATA BEFORE ANY UPGRADE!! should take my own advice 😉

I was able to fix it by going to the menu bar, clicking on MacOS Installer and choosing Quit Installer. Then a log appeared, and a message saying to try to restart from a different disk. I clicked on Utilities in the menu and chose Startup Disk (I think), and chose my default hard disk to boot from. I was able to boot back into my computer successfully.

Apple: This wasn't easy to find!

I’m having the same issue with not being able to install High Sierra. I’ve tried to boot into safe mode but it isn’t working. I get to the log and then utilities and choose startup disk but it’s not showing anything in that startup disk box. I’m trying to somehow save all of the documents before I resort to formatting the disk and reinstalling everything. Any help is greatly appreciated

The fix that worked for me after "half" installing High Sierra, getting hung up and rebooting was a restart in Recovery mode - restart holding down Command + R until you see the recovery screen. One of the options in recovery mode is installing system software. This time it still took awhile but successfully completed. It begins the install in recovery mode, restarts the machine then takes about an hour or so to install.

This might be a dumb question but I'm having the same issues you had, and have a HDD that I've previously backed up to (but not recently, so I need to do it again), but how to I backup everything to the HDD while on the error screen? I did the "command f" that someone else mentioned and tried to do the Macintosh HD First Aid (but was told the Macintosh First Aid process failed) and am on the Disk Utility screen...

I'm really confused and nothing seems to be working!

Does it matter that the External harddrive already has a backup on it? It's a 1TB HDD and my laptop is only 500GB, and with the other backup there's still 878GB free, so can I just use this one?

Sorry, I tried calling Apple and they said I'd just have to wipe everything, so I'm hoping they're wrong!

Happened to me as well on my MacBook Pro. Got the package error trying to load the new OS Sierra. Ran First Aid on both hard disk and OS to get them mounted again and then reinstalled the OS Sierra after Recovery Mode hard restart and it’s working.

The reason the problem continues even after closing the installer is that the installer file is corrupt and the system is using it as the boot disk. The problem will continue until you set your computers System Disk as the boot disk. Here are the steps I used to set the boot disk.

Click the dialog box, not Restart. This causes a menu bar to appear.

Click Utilities and choose the Startup Disk option.

Choose your System Disk as the Startup disk.

Click Restart.

Once the system restarted, I downloaded and successfully ran the update.

I have done what AFNG suggested:

Switched off the computer by pressing the on/off button. Wait a few seconds.

Then switch on again by pressing shift and on/off button together. Then wait for the computer to do its thing.

It seemed to crash again about twice then as nothing was happening for a long time, but I just repeated the process of switching off and then on again while pressing shift, and in the end it worked. It started to download the new MacOs.

But be patient. It took a few hours to complete the whole process.

Everything seems to be working just fine now!!