Question :

I have macOS 10.14 Mojave installed on my MacBook Pro ‘Mid 2012’, but every time I try to start up my Mac, it hangs when the progress bar (on the white startup screen with the Apple logo) is at 99%…

On the TechRadar-website I found some startup key-combos to try : https://www.techradar.com/how-to/computing/apple/how-to-use-os-x-boot-options-to-troubleshoot-your-mac-1305645

I have tried the following, but it didn’t help :

• restarting my MacBook
• zapping the PRAM / NVRAM
• running Disk First Aid in Recovery Mode
• running Disk First Aid from another Mac while in Target Mode
• reinstalling macOS Mojave from Recovery Mode
• reinstalling macOS Mojave from a USB installer

So far, no problems where found, but the exact same problem keeps occuring :

When I startup my MacBook Pro, the progress bar goes quickly to 50%, then slows down but still keeps progressing up to 99% or even 100% and then hangs…

What can I do to solve this ?

Answer :

You have already tried most of the options that usually give success when you encounter these types of problems, so you have little options left to choose from.

——————- U P D A T E ——————-

If you get to see a progress bar while your Mac hangs, do as outlined below, but  if your Mac hangs before you see a progress bar below the Apple logo, have a look at this post first :

fixed : MacBook Pro sighs then hangs during startup without progress bar over and over again

——————- ORIGINAL POST ——————-

The first thing to try would be ‘Verbose Mode’ so you will be able to figure out what problems are encountered during startup :

• shut down you Mac using the power button
• startup your Mac in Verbose Mode by pressing the [CMD]+[V] keycombo on your keyboard during startup
• now, your Mac starts up without a GUI (Graphic User Interface) but just displays lines of code (like in the Terminal.app and Console.app)
• note that you might see a screen of code flashing by and than face your regular inlog screen… if so, just login and you will get to the Console-like black screen with white lines of code…
• wait for the lines of code to halt and see what error messages are displayed in the final lines of code
• if the error is “too many corpses being created”, use the solution outlined below (additional error terms are “Process”, “crashed:” and “opendirectoryd.”)
• if you get any different error message : lookup the error message and the solution on the internet

The solution to the “too many corpses being created” startup-error :

• shut down your Mac using the power button
• startup your Mac in Recovery Mode by pressing the [CMD]+[R] key combo on your keyboard during startup
• if FireVault is on, mount the HardDisk by clicking Disk Utility.app and then typing your password
• then, go to Utilities in the top menu bar and click Terminal in the pulldown menu
• in Terminal.app type this line of code (in which “Macintosh\ HD” is replaced by the name your have given your HardDisk ; the default name is “Macintosh HD”, and note that all spaces in the name of your HardDisk should be replaced by “\ ” (a backslash + a space) when typing these lines of code) :

cd /Volumes/Macintosh\ HD/var/db/caches/opendirectory

• then press the [Enter]-key to run the code
• when the cursor returns on the very next line you’re good, if you get an extra line in between, you’ve run into an error (e.g. “command not found” usually means you mistyped something, so you should just try again ; if you forgot to replace the space in your HardDisk’s name by “\ “ you’ll also get an error and you should just try again)
• on the next line, type this :

mv ./mbr_cache ./mbr_cache-old

• then press the [Enter]-key
• when the cursor returns on the very next line you’re good
• again, if you get an extra line in response, you’ve made an error and trying again with greater accuracy will probably solve it…
• then, exit Terminal.app by pressing the [cmd]+[Q] key-combo
• then restart your Mac by clicking on the Apple-icon top left in the top menu bar and clicking “Restart” from the pull down menu
• now your Mac should startup without problems
• note that the first startup will take a little longer, as all system settings need to be rebuilt

That’s it !

enjoy 😉