Mac Installer: An error occurred while preparing to install.

If you want to reinstall macOS on an Apple Mac, then this error message may thwart your plans: An error occurred while preparing to install. Try to run the program again. - But it is no reason to despair. The error, which is not further named by the message, is found quickly and can be eliminated without too much effort. In this guide, I'll show you how to do it. 

An error occurred while preparing to install. Try running the program again. – This error message in the Mac Installer ensures that macOS cannot be installed. You can find and fix the error on Mac, iMac and MacBook via

Terminal in recovery mode." width="1024″ height="484″ /> There was an error preparing to install. Try running the program again. - This error message in the Mac Installer causes macOS to fail to install You can find and fix the error on Mac, iMac and MacBook using the terminal in recovery mode.

Common reason for "An error occurred while preparing the installation ..."

Probably the most common reason for the warning “An error occurred while preparing to install. Try to run the program again. ”Is an incorrect system time. If the time in the Apple Mac has been changed by resetting the computer, replacing the system hard drive or some other measure, you can easily change it to the current date and time.

Start Mac in recovery mode

If you hold down the key combination Command + R (or cmd + R or ⌘ + R) when starting the Apple Mac, you will enter recovery mode. You can find details on this in this post. If that worked, you will find, among other things, the menu bar in which you can find under Utilities the point Port selects.

Get and set Mac system time in Terminal

To get the Mac system time, give her the command in the terminal data and press the Enter key. Now you can see whether the current date is correct with weekday, day, month, year and time. If it does not match the current data, enter the date command again, but this time with a character string that represents the current data.

This works according to this pattern: month-day-hours-minutes-year - with two digits for each value. For September 3, 2019, at 11:30 a.m., the command would look like this:

dates 0903113019

You confirm the whole thing again with Enter / Enter key. Then you can close the terminal and try the installation of macOS again. The error message should not appear again, but rather the installation of the operating system on the hard drive of the Mac, iMac or MacBook should go smoothly.


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  1. AnkelOndi says:

    Thanks a million ... the "date" theme has made me desperate with the old Mac for over a year ... now it is working again!

  2. Dominik says:


    I took it from the instructions and implemented it, it didn't work. Same message ...

    Best Regards


    • sir appleot says:

      Hello Dominik! I'm sorry. The instructions do not seem to cover all causes for this error message. If you can find out anything else that has helped you, I would like to add it here in the article.

    • goal says:

      Activate the partition in the partition program, enter the password and then install ... It worked for me!

  3. james says:

    Many thanks. I tried around for hours until I came across this article!

  4. Jan Wolf says:

    Hi, thank you in advance for the date, but now comes my next problem my mac is from 2009 OS X Yosemite is displayed during installation that the article is temporarily unavailable. Does anyone know what I can do now?

    • sir appleot says:

      Hello Jan! Try to start the Internet recovery with the keys Command + ALT + R when restarting. Then the Mac should actually install the latest system that is suitable for your Mac. Alternatively, you can also test Command + Shift + ALT + R, as I did here in the post have described. This will install the system that came with the Mac.

  5. falcoholix says:

    I'm trying an iMac Mid 2011 21,5 ″ which has now got an SSD, because the old HDD gave up, has to be recovered via the Internet.
    I can also select the SSD, it then starts with completely confused times (which also constantly jump back and forth) until it stops with the error message: "Additional components necessary for the installation of Mac OS X could not be loaded"
    I'm doing this for a friend of my daughter's and I'm not very apple-loving.
    Since I cannot and do not want to invest too much time, is there a quick & dirty method?

    • sir appleot says:

      Hello Falkoholix! I had the same thing with me 2-3 days ago. I couldn't do anything with the Internet restore because this message always came with the missing components. The solution for me: I made an El Capitan boot stick like it described here at Apple is. The installation went smoothly. DiskMaker X, which should actually be able to create boot sticks like this, also let me down. But the good news: El Capitan can still be downloaded using the link on the Apple site.

  6. MarkusK says:

    I exchanged the defective HD for an SSD in a MacBook Pro from 2012. The same mistake there too. Changing the date does not help, UTC is also displayed. Is this a problem?

    Activate partition and enter password: can you explain that in more detail? Do you have to enter or assign one?

    • Jen Kleinholz says:

      Phew ... which macOS do you want to install? Right now I don't know why the date doesn't help ... should actually. The one with the password should be the admin password that the Mac asks you for.

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