[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2016-07-06T18:42:47Z"
 content="""
annex.thin can only work on filesystems that support hard links,
so the most likely reason, from the information you have given,
is that the repository is on a FAT or other non-hard-link supporting
filesystem.

	joey@darkstar:~/tmp/xxx>date > bigfile
	joey@darkstar:~/tmp/xxx>git annex add bigfile
	add bigfile ok
	(recording state in git...)
	joey@darkstar:~/tmp/xxx>git commit -m add
	[master 39d19a4] add
	 1 file changed, 1 insertion(+), 1 deletion(-)
	 rewrite bigfile (100%)
	 mode change 100644 => 120000
	joey@darkstar:~/tmp/xxx>git annex unlock bigfile
	unlock bigfile ok
	(recording state in git...)
	joey@darkstar:~/tmp/xxx>ls -l bigfile
	-rw-r--r-- 2 joey joey 30 Jul  6 14:46 bigfile

It's working fine here as seen by the fact that bigfile
has a link count of 2 after being unlocked.

Other possibilies:

* If the repository was cloned using `git clone --shared`,
  annex.thin is not supported.
* If there are multiple files in the working tree that have the same
  content, annex.thin will only hard link one of them; the others
  will be non-thin copies.
"""]]