Odd folder named "lost+found" appeared after using El Capitan a couple of days

Question

Odd folder named "lost+found" appeared after using El Capitan a couple of days

I have two computers that have odd folders that appeared after installing El Capitan.

On the first computer after using El Capitan a couple of days yesterday an odd folder named "lost+found" appeared just inside the Macintosh HD. It contains a file called "iNode13853710." Does anyone know what this is and whether or not the folder and file are important to the computer? Can I trash these without consequences?

On the second computer there is a folder that is dated September 30, 2015 and was made at the time of installation. It is called "OS X Install Data" and is restricted for all users except the system. If I change the folder permissions, I see the following files:

Again does anyone know what this is and whether or not the folder and files are important to the computer? Can I trash these without consequences?

Sincerely,

Wilson

iMac, OS X El Capitan (10.11), MacBook Air, MacBook, & MacBook Pro

Posted on Oct 5, 2015 8:39 PM

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Answer 1

Oct 5, 2015 9:04 PM in response to over-repairs computers

lost+found is an old-school UNIX directory. It's typically hidden by default, and I don't know why it would be showing in your install.

inodes are how the file system keeps track of where files are located.

The things that you're seeing are quite strange. I don't know if it's disk corruption; any chance you're running some software like cocktail or other "maintenance" or "cleaner" software which may purport to optimize your system but are instead causing problem? If not, I think your disk may be bad; you may wish to run Disk Utility and have it verify your disk.

How old are your systems? Do they have SSDs or spinning disks? If the latter, I do suspect your disks may be going bad.

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Answer 2

leroydouglas

Level 10

199,560 points

Oct 5, 2015 9:29 PM in response to over-repairs computers

http://www.techradar.com/us/news/computing/apple/explained-lost-found-folder-in- os-x-712519

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Answer 3

Oct 5, 2015 9:30 PM in response to William Lloyd

The computer with the visible "lost+found" folder has an SSD and is maybe 7 months old. I do not use any "maintenance" or "cleaner" software either. I ran the Disk Utility from within the running computer. In El Capitan it does not give an option to verify the disk. However I ran "First Aid" and it found some sort of corruption that it fixed and a wrong file count that differed by one file. On rerunning "First Aid" it did not find any corruption, but it still had the differing file count in the disk hierarchy. A third run of the "First Aid" gave the same difference of count as shown below.

Finally on the other computer that has the folder labeled "OS X Install Data," it has a mechanical hard drive. Running Disk Utility's "First Aid" found all was OK and no errors.

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Answer 4

Oct 6, 2015 8:59 AM in response to over-repairs computers

Thank you William and Leroy. If I understand the article that Leroy referenced, then if the lost+found folder starts to fill with lots of files, I probably should reformat the SSD and do a clean install and then bring in my personal files again from Time Machine. I do have a question as to whether or not the discrepancy of file count is significant and thus would warrant now doing a clean install.

Thank you again.

Sincerely,

Wilson

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