So, you’ve upgraded the hard drive on your Mac. But when you try to install Yosemite, you run into trouble: a message stating, “An error occurred while preparing the installation.”
While that’s a vague message that could mean just about anything, OWC customer Jack H. points out that it could be just a matter of time. Your Mac’s clock, that is.
Jack brought the issue to our attention after he followed OWC’s instructional video for upgrading the internal hard drive on his MacBook Pro. After installing the new hard drive, he then attempted to re-install OS X Yosemite on the new drive, but was faced with the aforementioned error message. Often, this message is caused by simply an incorrect time and date on the MacBook.
Older Macs contain an internal PRAM backup battery to maintain system settings, such as the date and time when the computer is turned off. If that internal battery fails and needs replaced, the Mac will lose it’s date and time. On machines without a separate PRAM battery, there is a capacitor on the motherboard that performs the same function. In this case, your battery or power source charges the capacitor and it holds enough charge to keep proper time for a while.
Whichever of those two your Mac utilizes, following the steps below to reset your Mac’s clock should fix the time issue causing the error when installing OS X:
- Click on Utilities > Terminal
- When the terminal window opens, type date and hit enter. You will see that the listed date is incorrect, causing the reinstall error.
- To correct the wrong date, type date followed by MMDDHHMMYYYY (Month, Date, Hour, Minute, Year). Example: Enter 031918152015 for March 19, 6:15 p.m. 2015.
- Exit and then begin a new install. The issue should now be corrected.
Hat tip to Jack H. for bringing this issue and solution to our attention.