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Removing kext files via Terminal...is it safe?

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Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Sat Jul 04, 2020 5:49 pm

I just got my new mac up and running and tried to load the driver for a new Wacom tablet, to use with Logic as my old one doesn't work with Catalina. However, the installation kept failing. Doing some digging around online, it seems there is often a clash with a previous kernel extension which the Wacom installer doesn't remove. I checked the install log and indeed there are a couple of errors shown re: /Library/Extensions/SiLabsUSBDriver64.kext

The various forums say you can remove this kext using Recovery mode and terminal but I'm very nervous to delve into the mac's system like this. Is there a risk I may inadvertently do some serious kernel damage?

All advice gratefully received. Cheers
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Re: Removing kext files via Terminal...is it safe?

Postby desmond » Sat Jul 04, 2020 7:09 pm

Well, how much damage you do depends on what you do while you're there.

If you follow the instructions, things should be fine. You do, of course, have a full system backup in the event something happens, so you're covered either way.
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Re: Removing kext files via Terminal...is it safe?

Postby s_e_a_n » Sat Jul 04, 2020 7:25 pm

Do a full backup. Boot off the backup (hold option key while booting to choose alt drive). Drag kext from library out to desktop on your original drive. Reboot to original drive. If all goes pear shaped then put kext back where you got it. Ensure you try everything on your system before you overwrite the backup.
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Re: Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Sat Jul 04, 2020 7:47 pm

OK, thanks people. Sean, can you just go into a little more detail about what you mean? My understanding is you can't get at the kext files directly to drag them out of the library, even though you can see them there, you can only use terminal to remove them, and only via a Recovery boot process?

I seem to remember doing another Terminal job and had to disable and reenable SIP to do this, too?
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Re: Removing kext files via Terminal...is it safe?

Postby desmond » Sat Jul 04, 2020 8:10 pm

Dr Huge Longjohns wrote:OK, thanks people. Sean, can you just go into a little more detail about what you mean? My understanding is you can't get at the kext files directly to drag them out of the library, even though you can see them there, you can only use terminal to remove them, and only via a Recovery boot process?

Read his post again - he's not removing the kext file on the running system.
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Re: Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Sun Jul 05, 2020 2:26 pm

Yes I'm just not clear what he's suggesting I do. I just need it spelling out for my feeble brain to understand! :(
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Re: Removing kext files via Terminal...is it safe?

Postby desmond » Sun Jul 05, 2020 2:30 pm

Dr Huge Longjohns wrote:Yes I'm just not clear what he's suggesting I do. I just need it spelling out for my feeble brain to understand! :(

Make a backup of your system drive.

*Boot* from this backup copy.

Your system is now running from this copy, so the original system disk is just a plain old disk with files on it, which you can modify at will.

Once you've done what you need to do on the original system drive, you can go back to boot off it as normal.
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Re: Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Sun Jul 05, 2020 3:24 pm

Sorry I'm being really dense, but I don't understand. If I've got one system up and running how do I move files on the other one? I can only see one system on my monitor at a time?
Boot off the backup (hold option key while booting to choose alt drive). Drag kext from library out to desktop on your original drive.
This sounds like I'm using two systems at once??
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Re: Removing kext files via Terminal...is it safe?

Postby desmond » Sun Jul 05, 2020 3:30 pm

Dr Huge Longjohns wrote:Sorry I'm being really dense, but I don't understand. If I've got one system up and running how do I move files on the other one? I can only see one system on my monitor at a time?
Boot off the backup (hold option key while booting to choose alt drive). Drag kext from library out to desktop on your original drive.
This sounds like I'm using two systems at once??

Drive "ONE" is your system drive. You're booting your machine off it. You can't modify many files on this drive while the system is running of it.

Drive "TWO" is some other random drive.

You mirror ONE to TWO, so TWO is now an identical backup copy of ONE.

You now boot from TWO, meaning TWO is your (temporary) current system drive. Drive ONE is now just a random connected drive with files on it. While booted from TWO, use the finder to move whatever files around on ONE that you require. (I presume you know how to access files from different drives on your Mac.)

When you've finished modifying ONE, then reboot and go back to booting off your modified ONE as normal.

I'm not sure I can spell it out much clearer than this - I'm just rehashing the same step by step instructions multiple times... :protest:
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Re: Removing kext files via Terminal...is it safe?

Postby s_e_a_n » Sun Jul 05, 2020 6:57 pm

Thanks Desmond, sorry I didn't get back sooner but I've only now got back to my computer.

Huge, your "system drive" or "boot drive" is a hard drive containing the files which your computer needs to operate. It is often called Macintosh HD. It is referred to interchangeably as system drive (because it holds the operating system) or boot drive (because the computer boots, or starts up, using the files on it).

Many people also store other files on this hard drive and these are stored within the "user folder". MacOS allows you easy access to this user folder and has made access to other areas of your "system drive" difficult because people who didn't know what they were doing had a tendency to move things or delete things which the operating system needed... this could make your "system drive" unusable.

As Desmond has explained above, what I was suggesting was a way to make changes to your "system drive" without exposing yourself to danger as you would have a backup and could just reverse the steps you took if needed. If this is not clear to you and what I was suggesting does not make sense then I would suggest you get someone to help you with it.

I would strongly recommend that you do a bit of reading on the basic principles of MacOS and computers in general. Apple has (for better or worse) made the Mac usable by anyone and everyone and in doing so has hidden all the complexities of the computer underneath. This approach is fine for casual users and those who are happy to send emails and browse the internet. I'd suggest that anyone who is using a computer in a studio needs to either have a clear understanding of the operating system they're using or else have someone available who will look after this stuff for them.

I hope this helps and many thanks to Desmond for his clear input. I suppose what threw both myself and Desmond was your title. Even opening Terminal is daunting for most users so we had maybe assumed your level of knowledge was greater than it was. Whatever you do, don't mess around with Terminal unless you understand what you're doing! And no-one is suggesting you have a feeble brain, this stuff is not rocket science, it's just stuff you need to read up a bit on.
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Re: Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Sun Jul 05, 2020 7:09 pm

OK, thanks SEAN, clear now. My issue was simply that I wasn't aware that I would see the original HD on the backup system desktop too, in the normal way, but your post makes this clear.

I'm surprised that, in my research, I didn't find this solution to moving kernel extensions anywhere else? It seems like an easier, less risky option than the Terminal route?
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Re: Removing kext files via Terminal...is it safe?

Postby desmond » Sun Jul 05, 2020 7:35 pm

I don't see the terminal as some huge risk, you just need to be clear on what you are doing.

After all, it's just another way to telling your computer to do things.

But yes, if you need to modify the system, you either need to do it without the system running (ie, from a pre-boot condition like recovery console or whatever), or you do it from another system (ie, booted from a different boot drive).

It's always handy having a separate clean system you can boot into in case your current system messes up, and you can more easily to things to it, especially if you're not comfortable in the glorious land of unix...
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Re: Removing kext files via Terminal...is it safe?

Postby Dr Huge Longjohns » Mon Jul 06, 2020 11:25 am

Time Machine has saved my bacon on a number of occasions. Like when my new mac upgraded Logic to the latest version without asking me as I hadn't switched off auto updates yet!
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