Slow start MacBookPro Retina (Mid 2012)

Exactly the same issue with iMac Late 2012 27" i7. Wondering now about that pci pause:SDXC as well ...

Last night when I tried to restart my Macbook Pro (Late 2012) it paused on the gray screen with the apple and the "spinning grey gear" below it. When I used the Disk Utility, it said that my disk appeared to be okay (after verifying and repairing). Still wouldn't boot. Wouldn't boot in Safe Mode (I used Verbose Mode) and it kept getting stuck at the line "pci pause: sdxc". I used Single User Mode to verify/repair as well, and after that everything seemed to be booting fine - it started within 10 minutes. I decided to test it by rebooting again and it got to the login screen within 15 seconds.

All of these forum posts that I've seen online date from March 16th (2014) onwards... could there be something that is causing a more recent problem?

I'm bringing my laptop in to the local Apple repairer so that they can figure out what's going on, but hopefully we'll know at some point what it actually is and how to fix it.

Still having this problem on latest iMac i7 maxed out model.... Anyone find any kind of solution besides a clean reinstall...

I also have the same problem on My Mid-2012 MacBook Pro Core i5 w/ 10GB of RAM. This just recently started happening to me about a week ago. Right before the newest update of Mavericks. I was running Bootcamp with Windows 7 and noticed it first in Windows. Computer was running unbeliveably slow in both Windows and OSX which made me think hardware problem. I tested all removable components and all passed easily. I then re-partioned my dirve (deleting Windows) hoping that perhaps for some reason Windows had corrupted my HD. This did nothing. I then booted in verbose mode and safe verbose mode and saw the same pci pause lag in both. I have since done a verify disk and repair disk and both came back OK. I have asol repaired disk permissions. I have reset PRAM and SCM. I have witnessed a noticeable difference now after doing all of the above however my laptop is still freezing (finder not responding) frequently and web browsing is almsost unbearble with not responding on every page. My cold start time is currently at 2 min and 53 sec. prior to these issues my cold start time was about 45 secs.

There is a serious issue here and I'm not sure what it is. I am a computer technician with the majority of my experience being in Windows and Linux OS. So while I have no level of expertise in Mac OSX I will suggest that this appears to be an issue with the Mavericks OS. I never had performance problems before updating. Maybe a device driver conflict with the HD? Not sure but glad to see I'm not the only one plagued with this issue.

After some digging around I found that my system was missing a lot of core OS X files. This is extremely strange since I have been using Mavericks without any issues since Day 1. I decided to backup and reinstall OS X. The installation failed 3 times. Finally after 15 hrs Mavericks reinstalled. Problem still persisted. All of my apps ran without a hitch through spotlight, however finder was extremely buggy and sluggish not responding more than it was. Was finally able to get into "Library" and again noticed Mavericks was missing a multitude of core OS X files. Apple's answer to this issue (at least on other posts about this issue) is that the Mavericks installer used was probably corrupt during download. Keep in mind I downloaded three seperate times. Finally today I reinstalled again. All Core Files seem to be present and finder is working as it should. Problem seems to be resolved for me.

Unfortunately Problem came back. After several hardware tests I found that my 8GB after market RAM had bad sectors. Replaced with stock RAM and all was well. Unfortunately due to the bad RAM all my backed up files and applications are no longer functioning. They all seem to be corrupt in fact even any one of my backed up files or apps back onto my Mac causes hangs and freezing even when I'm not accessing them. So problem for me is officially resolved but at a loss. Thanks PNY for your **** RAM!

I *finally* fixed this. On my Mac mini it was so bad that booting was impossible.

Simply deleting /System/Library/Extensions/AppleSDXC.kext/ fixes it. My guess is that SD card **** don't work any more, but don't care what so ever.

Macbook pro, 13-inch, Mid 2012, i5 have the same problem, and I have to reinstall to fix it.

I have an Early 2011 Macbook Pro 15 and just bought the same MBP, but model Mid 2012 with an SSD. After I CCCed my original HD to the SSD and booted this in the Mid 2012, I got stuck for 6+ minutes during booting, before it resumed. CMD+V showed me it got stuck at pci pause: SDXC, as with the others here in this thread.

When I do a fresh install of 10.9.4 on the SSD, booting is as fast as expected. But as soon as I then use the migration assistant for migrating programs and data from the old HD to the fresh installed SSD, booting is afterwards again stuck at pci pause: SDXC.

I've done a **** of a lot of various attempts during the past 2 days (including deleting /System/Library/Extensions/AppleSDXC.kext), but could not find any remedy around the problem. This truly drives me crazy, specifically because all single attempts take at least a quarter of an hour because of the booting delay, and some even 2+ hours because of the installation and migration process... :-(

Sounds like you could have a failing HD which corrupted several files (system of otherwise). Unfortunately when this has happened to me in the past, all files on my HD were lost due to corruption. In fact moving the corrupted files onto a new HD could lead to corruption in the new drive. Best bet is to hook up the old HD, run disk utility and pray that it corrects any issues. Upload any imperative files from the old drive to the cloud (google drive, dropbox, etc) and download them one by one onto the new drive paying close attention to any erratic drive behavior. If you get lucky you be able to save some of your files. Also run a diagnostic test on your ram (command+D at startup) as this could lead to this behavior which may or may not be immediately apparent on a SSD due to the speed of the drive.

Thanks for answering: I can well imagine, that your experience was a really big nightmare. Specifically because the real reason appeared so badly hidden for long. Having said this, I do not believe, that I have the same problem. Both the system disk in my Early 2011 and the one in my Mid 2012 are SSDs, so failure is less likely. And I usually do heavy backups, and more important, no strange behavior has shown except for what I reported. So with me the reason most probably is something else.

In the meantime, I made some new experiments: I tested the correlation of the problem with 10.9.4, and the is some: I used a somewhat older (2 days) backup of the system disk, which is 10.9.3 and has not yet been upgraded to 10.9.4, and booted this in the Mid 2012. Et voilà, it did boot without the "pci pause sxrd" boot delay.

Right now I do a data-wise actualized copy of this backup onto the system SSD in the Mid 2012, and will use it as my working system )now I'm already 2 days without a computer!). I will refrain from upgrading it to 10.9.4, before having made several backups of it, and then I will do it testwise.

BTW: does anybody know, whether I still can get somewhere a 10.9.3 installation file for testing? The App store has now only 10.9.4 AFAIK.

Not sure if this helps, however I seemed to have this same issue. Isolated it to an external USB HDD, in fact, the one that comes with the iMac as its primary. I have it in a USB3 chassis. Unplugged it, it would boot fine, plugged it in, slow boot. I realized the chassis was powered on (power button was switched to on), even though it wasn't spinning or anything. I guess I'm used to just unmounting the drive and not powering it off. Turned it off, booted computer, boom, no problem. Not sure if that fix is specific to me, but I thought I'd throw it out there.

I also had this problem with my MacBook Pro with Retina display Late 2012 with Mavericks 10.9.4.
Im my case, the problem began right after I removed one of my Admin Users from my Mac.
I tried to restart with Shift + V, and I got the same "pci pause: SDXC" or something like that.

The startup was frozen in that line for about 5 minutes, and then it started.

Then, I tried to reset the PRAM, to verify the disk, to repair permissions, but nothing solved the problem.

The last thing I tried was to backup everything with TimeMachine and reinstall the system, then, boom! It worked!

Tip: backup, and reinstall the system (without deleting your users or files).

"Right now I do a data-wise actualized copy of this backup onto the system SSD in the Mid 2012, and will use it as my working system )now I'm already 2 days without a computer!). I will refrain from upgrading it to 10.9.4, before having made several backups of it, and then I will do it testwise."

I don't want to discourage someone from continued intensive trying, but on the other side, finally understanding that an effort will be in vain can also be helpful.

So I want to report, that I invested about 4 (four!) full working days for trying out with the migration assistant every kind of selected restore (all, programs, user data, system settings, and I believe any kind of permutation) into my fresh installed 10.9.4, and while there was sometimes temporary hope, at the end all efforts failed. So I had to bite the bullit and invest a further 2 full working days for setting my system again up from scratch with all my history, programs, settings, passwords, etc.pp... Unbelievable that I finally could recover everything (like license keys from several years ago)...

Since then everything is fine again, and as a half layman I can only speculate, that in my 8 years long always migrated system a hidden twist had happened and was hidden for long like a cancer, which may brake our only after years...