Hi guys, I tried to post this at various Mac forums, but I will also try this (probably hackintosh-oriented) one because of one simple reason - most people experienced this issue when building hackintosh. If it is not OK with rules, I am OK with deleting this. I also expect that hackintosh users will probably be more hardware and software-oriented and experienced than most mac users as hackintosh requires lots of skill. So let's see, maybe you can help me. Original post: Question is about Macbook Pro 13" early 2015 basic model, with 8GB RAM and basic i5. It had 256gb SSD when bought. tl,dr (I like to post tl,dr before the main text): Will not boot into OS X (stuck at 100% loading), will not boot into recovery (very slow loading, then stuck in 100%), will only boot single user mode or third-party OS (I tried Windows, Ubuntu), fan will not spin, I tried lots of stuff including SSD replacement, SMC and NVRAM reset and more. Verbose mode last line: ioconsoleusers gioscreenlockstate 3 hs 0 bs 0 now 0 sm 0x0 Long version: So the macbook will not boot up. It will reach 100% at loading bar and then stop forever. In verbose mode, the last thing it gives is ioconsoleusers gioscreenlockstate 3 hs 0 bs 0 now 0 sm 0x0 but honorable mention is also "kernel stall , (60s): 'IGPU' (later instead of 0 is 1,2,3, it will not show up after 3) because first it stops at kernel stall and after 2-3 minutes it continues some more lines and stops at ioconsoleusers. It does not move on since that. It will not boot into recovery mode! But it gets stuck at different part of the loading, then slowly advancing for 30 minutes until 100% loading bar and then stuck forever. It will not boot into safe mode, or any other mode I found on the internet BUT single user mode and diagnostic mode, these two will work. Another issue I noticed that the fan does not spin. I don't know if these two relate, because I tried to run another macbook pro (13" mid 2014 i5) with fan disconnected and it ran mac OS without problems. Of course I provided it sufficient cooling with every run since I found out about the fan (external fan, CPU was 22 degrees celsius, I will tell you later how I know that value). So I can spot 2 issues - probably some boot/possibly iGPU issue and fan issue. What I tried: For the fan not spinning: Diagnostic mode (D at startup) will run diagnostic for minute or two, interesting is that while the fan does not start spinning even in the diagnostic mode, it WILL spin in some part of the diagnostic (different RPMs - probably fan check). Then it will stop again. It will work in another Macbook Pro as well. But since I tested another one without any fan, I guess this is not related to boot issue. Diagnostic mode shown that my Mac is OK. For the boot issue: Of course SMC reset and NVRAM reset numerous times. Also tried SMC reset with removing battery (disconnecting battery cable and pressing power button) which is only for older macbooks. fscheck Replacing the SSD, I tried SSD with High Sierra and Mojave, I also tried to boot it from Mac mini in target disk mode, that Mini has Sierra. I tried all SSDs in the other Macbook Pro and they worked without issues. Booting from USB - Mac OS will not boot from thumb drive (it will stuck at loading, "surprisingly"). Booting into another OS from USB - it WILL boot Ubuntu live from thumb drive and Ubuntu will work seamlessly, but fans will not spin anyway. Booting into bootcamp Windows - I inserted another SSD that had High Sierra and Bootcamp Windows 8.1 on it - it will not boot into Mac OS, but it will boot into Windows 8.1 which will work without issues. This is the part when I finally found out if my cooling solution worked. It did, CPU did not exceed 40 degrees Celsius at load, 22 was idle temp. Damn, that is a lot better than stock cooling (part of credit to replacing thermal compound as I re-installed the fan)! Unfortunately not very practical. Interesting is that speedfan did not recognize any fans. Of course, fan did not spin in windows. I don't remember how many other solutions I tried, but definitely some more of them. Please, give me something. What I came up with - boot: maybe some GPU driver issue? But why - if the SSD boots fine in the other macbook? Is there any way to manipulate with drivers? I did once follow the tutorial from this forum to fix broken AMD GPU (turn it off permanently) via archlinux on my friend's macbook pro 15" 2011 but all I can do is follow instructions, so I cannot apply this on my macbook. What I came up with - fan: Probably bad firmware? This means I am f*cked, right? Because I cannot flash firmware on retina Macbook Pro, right? I thought maybe if I manage to fix the boot issue and boot into the system, and update or re-install the system OR at least access recovery mode, the firmware should be overwritten at some point of update/installation, right? Can it be something else than SMC firmware? Why did I not take it to the Apple authorized service station? First of all, I am from Slovakia. Our service stations are much less competent than the US ones, at least as far as I heard rumors (do not want to insult anyone, but that is said). I have reason to worry that they would take lots of money just for diagnostics and they would not want to dig deeply into the issue and would only offer me the logic board replacement (and ask more than the laptop's worth for it. As far as I know, Apple Genius is not available in my country. Second, I spent SO much time doing this that it would be a total failure if I had to go there anyway. That time would be counted wasted. I upload some photos of verbose mode screen.