Mac Pro 2008 El Capitan Kernel Loop

Have you checked your RAM?

Long ago, I had on a previous machine one of two chips go bad. This meant frequent kernel panics particularly when using applications that can use suddenly lots of memory like browsers.

The bad news is, back then, TechTools Pro consistently claimed the RAM was fine. A few tech savy recommended I not trust that. I tried the now old but still good "memtest" and it showed immediate failure. TT may be better at detection now.

If that is the case, your RAM may be under warranty--mine was.

I stumbled upon Rember. I will run it tonight and see what I can find out. It’s supposed to have the same programming code as memtest and mentions Memtest in the documentation.
Rember ran through and all RAM was OK. Now, is there a good app to check the Ethernet card? One thing at a time I (we) might get this figured out.
One thing I have noticed is the system prefs need to be rebuilt every other day. I don’t have an El Capitan install disk to do a clean install. Could constant freeze up and shut downs be software?
Breaking news! I found a couple of extensions that a trial VPN service had installed - tap.kext and tun.kext. Apparently they were auto loading something into the ethernet settings on every bootup. I removed these 2 kext files and have been running on Firefox, iTunes, TeamViewer for a couple of hours with no hiccups. Keeping my fingers crossed.
I’d really like to close out this thread!
It seems the crashing is narrowed down to whenever I use either Safari or Firefox. I can be using illustrator, photoshop, indesign, whatever I need for commercial printing and design work. But once I get on the internet, give it maybe 3 minutes and bam! Lockup and shut down. I put in a new PCIe network card but waiting for tech support to get me a driver for 10.11.6. It came with drivers up to 10.7. Hopefully then I will know if it’s the Ethernet card or not.
Ah c’mon Cheryl. You’ve always had something to input. You’ve helped me out a couple of other times
Tonight I was rebooting in Restore mode, attempting to reset Home Directory Permissions and ACL’s. Figured with all this rebooting it wouldn’t hurt anything. The screen started flickering like it always does right before it freezes and attempts a reboot but this time only 3-5 minutes in. It’s so hit and miss when it decides to go.
I’m trying to avoid an $80 diagnostic from the Mac tech but running out of ideas.
Does anyone know of an app to test the power supply or graphics card?
Figure this one out. I freeze up when using Firefox or Safari. But I’ve been on TeamViewer with my Mac at work for a couple of hours just fine.
TeamViewer went just over 2 hours before I froze up and shut down. I was thinking of totally removing Firefox and Safari but now with TeamViewer locking up, I’m thinking maybe my system is corrupt. I may have to buy an El Capitan disk and do a clean new install. My nephew installed the system last time and is halfway across the country.


Rosie Moderator
Staff member
Were you able to download the install file?
Do you have another Mac to use to do the download and save it to a flash drive. Then restart the computer and hold down the Coomand and R for recovery mode. Run disk utility, then quit disk utility. You should be able to insert the flash drive and install to your machine from the flash drive.
I will do that on my work Mac tomorrow.
Actually yes it did download. Can I put it on a 16gb flash card with a USB card reader or does it need to be a thumb drive?
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Well, I have the thumb drive working as a start up install drive and my Mac still will not keep running long enough to install the system. I talked to a Mac repair man who said it may be the riser cards or the GPU. I guess I’m done fussing with it and it’s time to take it in for service.
Mac Service guy said could be the graphics card but most probably the Riser Cards.
I see on eBay I can buy 2 riser cards with some RAM for around $50. That's the cheapest way to start. Better than buying a graphics card for $150+ and find out it's the riser cards.
Put the riser cards in today, also adding 8gb of RAM to the piddly 4gb I had. First noticeable difference was the Finder came right up instantly. Before, it took a good minute to open a folder or hard drive. Got the riser cards and RAM on eBay and they look absolutely brand new. 3 day delivery and $70 total charge, I feel good that this was the issue.


Rosie Moderator
Staff member
So far so good. Give it a couple of test runs and get back to us.
(remembering when 8 mb was the cat’s meow)