Won't boot after upgrade unless I delete hp_io_enabler_compound.kext

Hello Eric, thanks for your reply.

Customer came back this afternoon and, no surprise this time, the pesty file was back!!

Repeating the usual procedure this time didn't take more than 10 minutes:

• Start computer from rescue partition
• Launch Terminal.app
• Change dir to /Volumes/Macintosh HD/Library/Extensions and check for hp_io_enabler_compound.kext
• Remove .kext file
• Reboot computer

Looking into the update history I found that this time the AppStore had automatically updated the printers and have now set preferences to manual.

This ought to be a temporary fix because even a single Epson printer update brought back also the hp_io_enable_compound.kext extension file. Again!

Due to lack of time I have recommended customer not to update nor change anything for the time being, this issue however is real nasty. Will have to look into it again and in more detail, once more time will become available.

Will also need a suitable .pkg un-installer I guess

More in my next post

/P

I have had this same issue. Repeatedly.

Initially, after a update to OS X 10.11.1 the computer didn't want to boot.

Tried a further upgrade to macOS Sierra to no avail. Same problem.

After some searching on the Internet I found that removing all .kext files from the /Volumes/My_hardisk/Library/Extensions directory into a newly created Unsupported did the trick and could boot again.

I than updated the machine from 10.12.1 to 10.12.3 and, much to my surprise the Mac hung again pretty much the same way as before. Exploring the Extension folder I found the hp_io_enabler_compound.kext file which I removed swiftly into a another, newly created, directory. As to be expected this solved again the issue and the Mac booted no problem.

For the sake of testing (it was a customer computer) i tried to startup from the rescue partition and, using the DiskUtilities.app did a Disk Repair. It exited with no errors but now comes the weird part: at a further restart I found the pesty hp_io_enabler_compound.kext file again!

I had to repeat the same procedure (single user mode + terminal ) once more to erase the extension file and be able to boot again. Unbelievable!

It would be nice to better understand what is the mechanism built into the System that recovers this file doing a disk repair as I expect this to repeat again and again at every update.

Any ideas out there?

/P

I did check both and found nothing suspicious. Thanks for suggesting.

Please note that nothing bad happens after a new restart.

I can turn off and reboot the machine no problem.

It's booting from the Rescue Partition and performing a disk check that messed up things again.

I wonder how a disk check (and repair permission I guess) can restore a pesty file that has been removed.

/P

A workaround you could try is this: instead of finding where this driver comes from, just prevent it from being placed back. As root, after deleting the extension (the folder with the name hp_io_enabler_compound.kext) in the Extension folder, create an empty file with the same name:

# touch hp_io_enabler_compound.kext

Then remove all writing rights, even for the user:

# chmod ugo-w hp_io_enabler_compound.kext

And finally make it immutable at a system and user level:

# chflags schg hp_io_enabler_compound.kext

# chflags uchg hp_io_enabler_compound.kext

Unless the process that tries to copy it into the Extension folder will try a different name if it fails (like hp_io_enabler_compound_1.kext), it should just fail in placing it there again.

The problem is App Store applies a HP update software any time you delete that extension. So anytime you need to reboot the computer you have to check your extensions directory and see if hp_io_enabler is there and proceed to delete.

See if you can find the file(s) using one of these programs. If you go Finder/View/Show Path Bar, it will show you where it is located.

EasyFind – Spotlight Replacement

Find Any File

Are you running the latest version of the HP software? If you're not sure, check the App Store for an update.

I have the exact same problem. At first I was not sure which kernel extension caused the problem but after deleting one after another, hp_io_enabler_compound.kext turned out to be the culprit.

So after a reboot the startup progress bar hangs. I restart and start recovery mode (hold cmd + r when starting up). I open the terminal and navigate to

/Volumes/[volume name]/Library/Extensions

rm -rf hp_io_enabler_compound.kext

I've had the same problem: OSX didn't boot until I deleted the HP kext file.

To prevent the Mac AppStore to install that printer driver again I had to remove all HP Printers from System Preferences. Fortunately I don't remember where I used this printers anyway..

I have had this problem for a long time, and it followed me onto a new computer. I have been forced to restart from my old backup drive in order to get my new computer to function! Bizarre! I just deleted the printers from system preferences, let's see if that fixes it. Nothing else--deleting hp files, etc--has ever helped at all.

A printer doesn't need a kernel extension to print--those are all managed directly by Apple. It is likely for some "feature" of the printer, like some sort of hot button on the printer or maybe a card reader.

io means input/output, so it may be some sort of file transfer (like card reader).

The actual printer driver is separate and wouldn't be affected by uninstalling whatever Utilities the printer bundled with it. You would need to use the uninstaller provided by HP to get it to remove the file that is loading the kext.

It may be the HP printer utilities putting it back.

After a Disk check?

Hum..