My Mac Crashed Again
Jul 09, 2016
My Mac crashed again and won't fully boot, saying the drive is corrupt. I now suspect it's Photoshop that is causing this. The last time this happened, the night before I was working on a huge file and Photoshop started to tell me the file was too big, and then it was reporting it was unable to save the file. The next day, my machine wouldn't fully boot due to the keychain being corrupt.
This morning, I was working on a large Photoshop file and I started to get the same errors, when I rebooted, my keychain was corrupt.
I'm going to head into the Apple store and see if they can fix it without a reformat this time.
Why am I telling you this? Because I was going to put up the new podcast and that might not happen.
UPDATE
Back from the Apple store with a freshly reformatted machine and time machine pulled everything back.
I mentioned to the Genius Bar tech person that this is the second time it's hard crashed from editing a large file in Photoshop and he said "oh...", then we had a conversation that I can only assume was "off the record" by the way he spoke, tell me other people have reported drive corruption when extremely large files are process by fusion drives.
Yeah... no kidding.
I'll do a little Googling and see if I can find anything. Like I said in my previous post, I don't trust fusion drives and I guess with good reason.
I do need to re-edit the podcast, so that will go up tomorrow.
- Ron
PS: Do you mean that it might not happen at all, or not happen yet?
It *could* be that your hard drive is faulty and when your Mac is writing out the page file for VM swappiness, it corrupts the data, but that's unlikely if you're not getting corruption in other documents and random crashes all the time. I'm putting my money on bad RAM.
https://en.wikipedia.org/wiki/Memtest86
I've used TechTool Pro successfully to diagnose memory and HDD issues. I believe that the latest version supports Fusion Drives.
If I had to guess, I would say the problem is an edge-case within the immature technology of Fusion Drives (or their drivers). Since they try to keep in-memory cached images synchronised with the physical disk, there may be some conditions that cause them to go out of sync.
Whenever I get the itch to try one, I remind myself that it took 10 or 15 years for consumer-grade HDD and file-systems that support them to become reliable enough. Remember the time when sneezing close to the machine could corrupt your Master Boot Record?
-dZ.
When did you buy your iMac? Could this issue be related to yours?
http://www.theverge.com/2015/6/19/8815721/apple-replacement-program-imac-hard-drive
Basically, even if everything works absolutely perfectly, having two disks that rely on each other doubles your chances of disk failure. If one of them goes, your data goes.
Modern drives store a lot of bits on a tiny amount of space. In order to achieve this, they use a lot of questionably techniques. For example, instead of having two charges ("no charge" or "full charge") for one and zero, an SSD might charge the capacitors only partially to achieve four or more different states, store two or more bytes in one capacitor, and then fix the errors caused by them using statistical analysis ("this was most likely intended to be 01 when it was stored, but could also have been 00, and we'll pick the correct choice based on the parity bit).
So you already start out with disks that are very likely to eventually develop problems, and be unable to retrieve all of your data properly.
And then you add a second disk to this fragile system - if either disk fails, your whole system fails.
So these systems are a bad idea. I'm using a hybrid disk in my PS4, because it doesn't matter too much if the disk goes belly-up, but when my PC came preinstalled with a hybrid disk, I immediately took it out and put in a real SSD.
Completely unrelated but on a scale from "Huh?" to "Until hell..." how likely could it be, getting chip sound as an option on top?
have you tried using Affinity Photo (affinity.serif.com) instead of Photoshop?
I have switched last year, when it came out and never looked back at the subscription model ...
And Gary and David, I don't know what you find so funny, if you don't get back to work you'll both be joining Ron in detention, etc., etc.
Way less convenient, but if it happens a third time it might stop the fourth...
Though, I've always thought that a typical programmer would work on Linux. Maybe this has changed over the years in favor of Apple.
A simple script can test and discover the root of the problem (and crash your computer again)
But it is worth it. For science!
1. Format
2. Install Linux
3. Enjoy :D
I work professionally with Mac systems and can highly recommend you split the Fusion drive. I would use the SSD bit for the operating system and Apps, the spinning hard disk should be used to store all your data. I always mount the spinning disk to /User.
Get in touch if you want some help configuring this.
Best,
Marko