Q: I have to go in to single-user mode to boot in OS X.
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Jan 31, 2016 4:08 PMby Loner T,There is a process which is leaving the disk structures in an unknown state in OS X, which is causing the OS to protect itself by making the disk partition/OSX to become read-only. It could be third-party software, it could be a missing patch. It could also be a hardware issue, where disk commands are being lost.
There is a command called sync which should be called to clean disk queues. Failures of sync can be many. This is the man page of sync.
SYNC(8) BSD System Manager's Manual SYNC(8)
NAME
sync -- force completion of pending disk writes (flush cache)
SYNOPSIS
sync
DESCRIPTION
The sync utility can be called to ensure that all disk writes have been completed before the processor is
halted in a way not suitably done by shutdown(8). Generally, it is preferable to use shutdown(8) to shut
down the system, as they may perform additional actions such as resynchronizing the hardware clock and
flushing internal caches before performing a final sync.
The sync utility utilizes the sync(2) function call.
SEE ALSO
fsync(2), sync(2), shutdown(8)
HISTORY
A sync utility appeared in Version 4 AT&T UNIX.
BSD May 31, 1993 BSD
The next time we do the read-write trick, we should also run sync (three times) before we go back into normal mode.
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Feb 1, 2016 6:27 PMby DwaynXD,Sorry for the late reply. I am sorry but I am to afraid of making this worse by doing this method. Everything is working fine on Windows which I use the most. And can you please answer this question? : Is it OK to keep typing the 2 command in single-user mode every time I want to boot up in OS X? (/sbin/mount -uw / and exit)
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Feb 1, 2016 6:35 PMby DwaynXD,Whoops, ignore my last comment. I did not see that the page turned to number 6. But I am un-sure of what I can do, I don't want to do a fresh install where it can cause more problems. If there are no more solutions to this, I am sorry to say but that I have wasted your time. I don't want to do a fresh install in which I can mess things up. If there are no more solutions, you can close this thread.
I really don't know what to do now...This thread has been going on for almost a month now and almost a 1000 views but still no solution. Only headaches.
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Feb 1, 2016 6:50 PMby Loner T,My suggestion is to install OS X on an external disk, leaving your internal disk untouched. If the external disk OS X and your internal disk Windows can switch without this issue, you will need to re-install OS X on the internal disk.
You can continue to manually type those commands, if that is what you choose.
Can you describe when this problem first started and what events took place prior to this problem happening?
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May 15, 2016 9:43 PMby pdxBug,Hi there -
This thread has been very helpful. Just want to report out a similar problem and hopefully there is a solution for my problem.
1. I bought a used MBP (mid 2014) recently. The machine has been running fine.
2. I came back from a trip and realized a "software update" process was running in the background which was eating up a lot of CPU cycle.
3. Force quit after letting it run for few hours but nothing was changed nor there was any reboot.
4. Shutdown and restarted.
5. Then I can boot back to OS X.
6. After many trials and errors (like fsck, disk util..etc) , I realized I had to a) boot into single user mode b) set "mount -uw /" and c) then "exit". Then it automatically boots back to OS X.
I am not running dual boot. But since the symptom was very similar to what DwaynXD is experiencing, I am wondering if it had a dual boot at one point.
