Deleting the ._* files from a mounted volume kinda screwed some things up I have a thumb drive that I use frequently, which results in a lot of the ._* files being created, which I periodically delete by executing something like find /Volumes/Secure -name '._*' -exec rm -vf {} \;, and I've never had that ruin anything before. However, it looks like something may have gotten broken during this last execution.

Heres the console output of the find/rm command:

[Tue Aug 14 09:39:12]{1:126}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ find -d . -name '._*'
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/startupCache/._startupCache.8.little
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/safebrowsing/._test-malware-simple.pset
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/safebrowsing/._test-phish-simple.pset
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/safebrowsing/._test-unwanted-simple.pset
# TRUNCATED
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/safebrowsing-to_delete/._test-flashsubdoc-simple.pset
./tor/TorBrowser-Data/Browser/Caches/1blvjd07.default/safebrowsing-to_delete/._testexcept-flashsubdoc-simple.pset
[Tue Aug 14 09:39:18]{1:127}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ find -d . -name '._*' -exec rm -vf {} \;
find: .: Invalid argument


(Not sure, but maybe it has something to do with the {} not being in quotes? I can't remember if I used quotes in the past)

When I mount the volume, I can see the contents just fine as long as I'm not referencing the content using a relative path while I'm in the mounted volume (PWD).

Here's an example of what I mean. You can see that I can list the contents of /Volumes/Secure just fine. But if I cd to it, then try to list the content of the current directory, it doesn't work:

[Tue Aug 14 09:46:02]{1:193}jdoe@MacBook-Pro:/Volumes(✓)$ df /Volumes/Secure
Filesystem   512-blocks    Used Available Capacity iused ifree %iused  Mounted on
/dev/disk4s1   35372096 1566528  33805568     5%       0     0  100%   /Volumes/Secure
[Tue Aug 14 09:46:06]{1:194}jdoe@MacBook-Pro:/Volumes(✓)$ ls /Volumes/Secure
chemdocs             credentials          data.tar.gz.enc      scripts              test                 test-data            test-data.tar.gz.enc tor
[Tue Aug 14 09:46:09]{1:195}jdoe@MacBook-Pro:/Volumes(✓)$ cd /Volumes/Secure
[Tue Aug 14 09:46:11]{1:196}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ ls
.


Then, just to make this a little more confusing and frustrating, it seems to be intermittent...

[Tue Aug 14 09:46:09]{1:195}jdoe@MacBook-Pro:/Volumes(✓)$ cd /Volumes/Secure
[Tue Aug 14 09:46:11]{1:196}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ ls
.
[Tue Aug 14 09:52:28]{1:27}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ ls .
.
[Tue Aug 14 09:52:30]{1:28}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ ls -alrth .
total 30240
drwxrwxrwx  1 jdoe  staff    16K Jun 18 18:20 .Spotlight-V100
drwxrwxrwx  1 jdoe  staff    16K Jul  3 12:10 test-data
drwxrwxrwx  1 jdoe  staff    16K Jul  3 12:10 .info
# TRUNCATED SOME LINES
drwxrwxrwx  1 jdoe  staff    16K Aug 11 03:41 .Trashes
drwxrwxrwx  1 jdoe  staff    16K Aug 11 03:41 .TemporaryItems
drwxrwxrwx@ 1 jdoe  staff    16K Aug 13 19:22 .
drwxrwxrwx  1 jdoe  staff    16K Aug 14 09:43 .fseventsd
drwxrwxrwt@ 7 root     admin   238B Aug 14 09:43 ..
[Tue Aug 14 09:52:32]{1:29}jdoe@MacBook-Pro:/Volumes/Secure(✓)$ ls -alrth ./
ls: ./: Invalid argument
[Tue Aug 14 09:52:34]{1:30}jdoe@MacBook-Pro:/Volumes/Secure(0)$ ls -alrth .
ls: .: Invalid argument
[Tue Aug 14 09:52:36]{1:31}jdoe@MacBook-Pro:/Volumes/Secure(0)$ ls -alrth .
ls: .: Invalid argument
[Tue Aug 14 09:52:37]{1:32}jdoe@MacBook-Pro:/Volumes/Secure(0)$ ls
.


(Here's a gist with some extra console output)

I've tried unmounting and remounting with no success. 

Any input would be appreciated, thank you!

-J

Update
I just noticed something else thats rather interesting... These problems I showed above are all exclusive to the CLI. I can open the mounted drive in Finder and explore it just fine.. Odd.
The symptoms you describe are the signs of a corupted filesystem, which is the
usual fate of frequently used USB key.

Make a backup of your USB key,
and run an fsck or Disk Utility on your file-system.

I even advise you to completely check it with:

• full backup,

• full secure erase with one pass of 0 (to be sure to write on all blocks),

• make a new FS,

• recover from backup.

Your find doesn't cause any trouble, since -exec argument isn't evaluated by a shell, you dont have to protect it against evaluation.