My MacBook white cannot boot up and shut down during boot up process. I decided to handle it in Single Mode using boot up keys Command + S.
After a couple rounds of fsck checkups, it still showed up with error like "disk0s2: I/O error".
It was hopeless that fsck didn't try the best to repair the problems. I felt terrified when the other users suggests things like Reinstall Mac OS or buying a big external drive to backup what I have on the hard drive which was suspected to be damaged.
One post with a success gave me hope while I bumped into a post which suggested that fsck can force to repair errors with special options.
Pressing Command + S during boot up to enter Single mode and try the following command:
$ /sbin/fsck_hfs -dryf /dev/disk0s2
The device name disk0s2 may be varying depending on your MacBook model and configurations. As discussed on the forum, this command may need to run multiple times to have a successful repair.
After a series of 'orphaned file hard link', 'Missing thread record', 'Invalid directory count' messages, messages like '*****The volume was modified ****' and 'repaired successfully' was finally shown up on the screen. It's now ready to reboot the machine to see if the system boots properly.
$ reboot now
Here's the reference of fsck_hfs command:
fsck_hfs
File System check for HFS and HPFS+ (high performance file systems
fsck_hfs -q [-df] special ...# check if clean unmount
fsck_hfs -p [-df] special ... # check for inconsistencies only
fsck_hfs [-n | -y | -r] [-dfgxlES] [-D flags] [-b size] [-B path] [-m mode] [-c size] [-R flags] /dev/disknsp …
# repair inconsistencies
Example:
> sudo /sbin/fsck_hfs -d -D0x33 /dev/disk0s10
journal_replay(/dev/disk0s10) returned 0
** /dev/rdisk0s10
Using cacheBlockSize=32K cacheTotalBlock=32768 cacheSize=1048576K.
Executing fsck_hfs (version hfs-305.10.1).
** Checking non-journaled HFS Plus Volume.
The volume name is untitled
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume untitled appears to be OK.
CheckHFS returned 0, fsmodified = 0
Preens the specified file systems. Started by fsck(8) from /etc/rc.boot during boot
Fix common inconsistencies for file systems that were not unmounted cleanly. If more serious problems are found, fsck_hfs does not try to fix them, indicates that it was not successful, and exits.
With no options check and attempt to fix the specified file systems.
-d debugging information.
-D flags extra debugging information.
0x0001 Informational
0x0002 Error
0x0010 Extended attributes
0x0020 Overlapped extents
0x0033 include all
-b bytes size of the physical blocks used by -B
-B path Output the files containing the physical blocks listed in the file path.
The file contains decimal, octal (with leading 0) or hexadecimal (with leading 0x) physical block numbers, separated by white space, relative to the start of the partition, For block numbers relative to the start of the device, subtract the block number of the start of the partition.
The size of a physical block is given with the -b option; the default is 512 bytes per block.
-f with -p force check of `clean' file systems,
otherwise force check and repair journaled HFS+ file systems.
-g generate output strings in GUI format. This option is used when another application with a graphical user interface (like Mac OS X Disk Utility) is invoking the fsck_hfs tool.
-x generate output strings in XML (plist) format. implies -g
-l Lock down the file system (not limit parallel check as in other versions of fsck> and perform a test-only check. This makes it possible to check a file system that is currently mounted, although no repairs can be made.
-m rwxrwxrwx permissions for the lost+found directory if it is created (suggest 700 ed). orphaned files and directories are moved to the lost+found directory (located at the root of the volume). The default mode is 01777.(bad)!
-c size size of the cache used by fsck_hfs internally. Bigger size can result in better performance but can result in deadlock when used with -l. Decimal, octal, or hexadecimal number.
If the number ends with a k,m or g
-p Preen the specified file systems.
-q Causes fsck_hfs to quickly check whether the volume was unmounted cleanly. If the volume was unmounted cleanly, then the exit status is 0. If the volume was not unmounted cleanly, then the exit status will be non-zero. In either case, a message is printed to standard output describing whether the volume was clean or dirty.
-y Always attempt to repair any damage that is found.
-n Never
-E exit (with a value of 47) if it encounters any major errors. A ``major error'' is considered one which would impact using the volume in normal usage; an incon- sistency which would not impact such use is considered ``minor'' for this option. Only valid with the -n option.
-S scan the entire device looking for I/O errors. It will attempt to map the blocks with errors to names, similar to the -B option.
-R flags Rebuilds the requested btree. The following flags are supported: a Attribute btree
c Catalog btree
e Extents overflow btree
Requires free space on the file system for the new btree file, and if fsck_hfs is able to traverse each of the nodes in the requested btree successfully. Rebuilding btrees is not supported on HFS Standard volumes.
-r Rebuild the catalog btree. This is synonymous with -Rc. Because of inconsistencies between the block device and the buffer cache, the raw device should always be used.
Example:
> sudo fsck_hfs -l -d -D 0x0033 -B ~/.profile /dev/disk0s8
0 blocks to match:
** /dev/rdisk0s8 (NO WRITE)
Using cacheBlockSize=32K cacheTotalBlock=32768 cacheSize=1048576K.
Executing fsck_hfs (version hfs-305.10.1).
** Performing live verification.
** Checking Journaled HFS Plus volume.
The volume name is DATA
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
Orphaned open unlinked file temp7479645
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
invalid VHB attributesFile.clumpSize
Volume header needs minor repair
(2, 0)
Verify Status: VIStat = 0x8000, ABTStat = 0x0000 EBTStat = 0x0000
CBTStat = 0x0000 CatStat = 0x00000000
Volume header needs minor repair
(2, 0)
Verify Status: VIStat = 0x8000, ABTStat = 0x0000 EBTStat = 0x0000
CBTStat = 0x0000 CatStat = 0x00000000
** The volume DATA was found corrupt and needs to be repaired.
volume type is pure HFS+
primary MDB is at block 0 0x00
alternate MDB is at block 0 0x00
primary VHB is at block 2 0x02
alternate VHB is at block 88769454 0x54a83ae
Volume header needs minor repair
(2, 0)
Verify Status: VIStat = 0x8000, ABTStat = 0x0000 EBTStat = 0x0000
CBTStat = 0x0000 CatStat = 0x00000000
** The volume DATA was found corrupt and needs to be repaired.
volume type is pure HFS+
primary MDB is at block 0 0x00
alternate MDB is at block 0 0x00
primary VHB is at block 2 0x02
alternate VHB is at block 88769454 0x54a83ae
sector size = 512 0x200
VolumeObject flags = 0x07
total sectors for volume = 88769456 0x54a83b0
total sectors for embedded volume = 0 0x00
CheckHFS returned 7, fsmodified = 0
> echo $?
8
EXIT VALUES
0 No errors found, or successfully repaired.
3 A quick-check (the -n option) found a dirty filesystem; no repairs were made.
4 During boot, the root filesystem was found to be dirty; repairs were made, and the filesystem was remounted. The system should be rebooted.
8 A corrupt filesystem was found during a check, or repairs did not succeed.
47 A major error was found with -E.
