Every few restarts, Mac won't start up, unless I reset PRAM

[Gary King]

For some reason, every few times (let's say every 5 times) I restart my Mac Mini (running MacOS High Sierra 10.13.3, on an SSD), the startup screen will get stuck on the white loading bar with a black background, with the white bar at 100% full and just sitting there for minutes (the longest I left it on that screen is about an hour, and I wasn't willing to wait any longer).

If the startup screen is stuck, and then I force my Mac off and turn it on, then it just gets stuck there again, once the loading bar reaches 100%. The only way to bypass this is to reset my Mac's PRAM. Then when I start up the Mac again, it loads fine.

Why does this happen? And how can I fix it? Unfortunately, I'm not sure when this started happening, since I rarely restart my Mac, except when I update it. I only Sleep my Mac every night.

My Mac's memory is actually brand new (it's a few days old), and I have already ran a Mac Hardware Diagnostic anyway, and it said there were no problems.

 

[techwarrior]

Any chance you have some old drivers (kext) on your system that are no longer supported?

A while back, I had issues with a Mini I restored from a hackintosh backup and when I upgraded, System Integrity prevented these from loading, thus stalling my boot up.

To fix it, boot into Safe Mode (hold SHIFT while booting). Safe mode bypasses loading third part drivers (usually). Open Terminal, and find all non-apple Kexts:

kextstat | grep -v com.apple

In the resulting list, you will find low level drivers for things like AntiVirus, Virtualization software (VMWare, Parallels, Virtual Box), and other things that might be non-native. Start with the most obscure items, delete them and then see if that fixes it. Repeat until you are healthy again. In particular, if there was an app or hardware you recently installed, this would be the most likely culprit.

To unload a kext, assuming it is in /System/Library/Extensions (most are here):

sudo kextunload /System/Library/Extensions/NAME_OF_THE_KEXT_FILE.kext (provide your Admin account login when prompted)

Then, remove the kext folder using:

sudo rm -r /System/Library/Extensions/NAME_OF_THE_KEXT_FILE.kext

Then reboot normally.
[doublepost=1519164489][/doublepost]BTW, PRAM reset, like Safe mode, bypasses loading third party kexts in the boot process, waiting instead until the app launches (either manually or in your login items).

 

[fisherking]

new ram? seems too coincidental that the problem is happening with the new memory. as much a nuisance as it is... you might put the original ram back in, see if the problem persists (or not).

 

[techwarrior]

new ram? seems too coincidental that the problem is happening with the new memory. as much a nuisance as it is... you might put the original ram back in, see if the problem persists (or not).

Agreed, but if he rarely reboots and has the issue 1/5 times, this has been going on for a while. The memory was upgraded just a few days ago, so not likely the issue. Nevertheless @Gary King this is not a bad suggestion if it correlates to your problems.

One more thing you can try is to boot into recovery, and re-install the OS (don't reformat the drive). What this will do is ensure you have good OS System files that might have become corrupted. Your apps, settings and files will remain in tact if you don't reformat the boot drive.

 

[claaariii]

Hey! I know it’s been a while, but I’m having the same exact issue, also on a 2014 Mac Mini. It works perfectly fine, but only starts up normally after a PRAM reset. (EVERY single time). Did you ever figure out what the issue was? Or what ended up “happening” to the Mini? From what I’ve read I’m thinking it’s probably the PRAM battery, but I don’t know what happens if I just leave it/keep using it like this. I’m also “scared” of doing any updates that require restarts, as I don’t know if zapping the PRAM during that will affect/break anything…

Last I checked, it wouldn't boot into safe mode OR recovery mode either... but I don't wanna play around with it too much once it does start up fine after the PRAM reset. I'm just trying to leave it on and not sleep either (since the issue started with it not waking from sleep...).

Thanks in advance for any info!

 

[Taz Mangus]

Hey! I know it’s been a while, but I’m having the same exact issue, also on a 2014 Mac Mini. It works perfectly fine, but only starts up normally after a PRAM reset. (EVERY single time). Did you ever figure out what the issue was? Or what ended up “happening” to the Mini? From what I’ve read I’m thinking it’s probably the PRAM battery, but I don’t know what happens if I just leave it/keep using it like this. I’m also “scared” of doing any updates that require restarts, as I don’t know if zapping the PRAM during that will affect/break anything…

Last I checked, it wouldn't boot into safe mode OR recovery mode either... but I don't wanna play around with it too much once it does start up fine after the PRAM reset. I'm just trying to leave it on and not sleep either (since the issue started with it not waking from sleep...).

Thanks in advance for any info!

A few things to try:

1. Boot into Recovery Mode, open Disk Utility and run First Aid. See if that finds and corrects anything.
2. Next try restarting to Diagnostics. Run diagnostics and see it is finds any issues.
3. Next try creating a clean new user account, restart the computer and login to the new user account. In the new user account, does the issue still happen? If it does not, then the issue is related to your current user account. In that case:
   • Remove all items listed in your System Preferences→Users & Groups→<your user name>→Login Items.
   • Copy all the files in <your user account>/Library/LaunchAgents to your Desktop/LaunchAgents folder. Move all the files in <your user account>/Library/LaunchAgents to the Trash and empty the Trash.
   • Restart the computer.
   • Login to your user account and add back in one item to your Login Items, logout and login again. See which added item might be causing the issue.
   • Login to your user account and add back in one item to your <your user account>/Library/LaunchAgents, logout and login again. See which added item might be causing the issue.
4. The other thing I would suggest is create a new partition, boot into Recovery Mode, install High Sierra to the new partition and restart to the new partition. Setup the clean OS install as a new computer (don’t install any third party software). See if you have the issue happen in the clean install. This will tell you if the issue is related to having any third party software installed. When you are done restart back to your current install and remove the new partition. Once you restart back to your current install.
5. If you found that the clean install worked then the issue could be related to the files in the /Library/LaunchAgents and/or /Library/LaunchDaemons. The items in those folders are executed when you restart the computer before you login to your use account. Apply the same thing here by copying over the files to your Desktop and move them to the Trash. Restart and copy back in one file, restart and see if the issue happens. Keep doing this until all files are copied back.

How to repair a Mac disk with Disk Utility - Apple Support

Use the First Aid feature of Disk Utility to find and repair disk errors.

support.apple.com

Use Apple Diagnostics to test your Mac - Apple Support

Apple Diagnostics, formerly known as Apple Hardware Test, can check your Mac for hardware issues.

support.apple.com

How to reinstall macOS - Apple Support

You can use macOS Recovery, your computer's built-in recovery system, to reinstall the Mac operating system. Reinstalling macOS doesn't remove your personal data.

support.apple.com