OS X fails to open quarantined files

Question

Hi,
Since doing a fresh install of snow leopard on release date I have had several problems with the OS X I have googled but can't seem to find any reference to this issue;
When I first boot into OS X everything works fine and it stays that way for hours or days, then all of a sudden files with the "com.apple.quarantine" attribute fail to launch; if I try to run an app with the flag then it hangs and if I try to open a PDF for example, then preview will fail to open it and hang.
If I kill the process, remove the com.apple.quarantine attribute with xattr then the file works fine, however this is clearly inconvienient. The only way I can fix the issue is to reboot my system when it occurs.

Answer 1

http://images.apple.com/server/macosx/docs/LeopardSecurity_Config20080530.pdf
"Applications that download files from the Internet or receive files from external sources
(such as mail attachments) can use the Quarantine feature to provide a first line of
defense against malicious software such as Trojan horses. When an application receives
an unknown file, it adds metadata (quarantine attributes) to the file using new
functions found in Launch Services.
Files downloaded using Safari, Mail, and iChat are tagged with metadata indicating that
they are downloaded files and referring to the URL, date, and time of the download.
This metadata is propagated from archive files that are downloaded (such as ZIP or
DMG files) so that any file extracted from an archive is also tagged with the same
information. This metadata is used by the download inspector to prevent dangerous
file types from being opened unexpectedly."
Here is a possible solution...
-mj