Mine looks like this:
drwx------ 251 stefan staff 8534 27 Jul 15:29 ByHost
And the first few lines look like this:
drwx------+ 763 stefan staff 25942 27 Jul 15:41 .
0: group:everyone deny delete
drwx------@ 60 stefan staff 2040 25 Jul 09:27 ..
0: group:everyone deny delete
But as I said in my initial post, such errors do not only appear for the ByHost folder. It happens for various preferences, for example, when Spotlight indexes a M4V movie and tries to create/access a codec property file. Or here are some other examples when Safari is running:
sandboxd (): Safari Webpage P(4152) deny file-read-data /Users/stefan/Library/Preferences/com.apple.DownloadAssessment.plist
Jul 27 12:41:16 neptun sandboxd (): Safari Webpage P(4182) deny file-read-data /Applications/Safari.app/Contents/Resources/Defaults.plist
Jul 27 12:41:16 neptun sandboxd (): Safari Webpage P(4182) deny file-read-data /Applications/Safari.app/Contents/Resources/English.lproj
Here's one more:
sandboxd (): mdworker(5427) deny file-write-create /Users/stefan/Library/Preferences/com.cod3r.a52codec.plist.imarlP7 (Importing type 'com.apple.m4v-video' using 'file://localhost/System/Library/Spotlight/CoreMedia.mdimporter/' - diagnostic:0 - find suspect file using: sudo mdutil -t ...)
For what it's worth, I'm getting those errors too. Mine are sandboxd based and hit through either Safari trying to write to /private/vars/folders/zz
I am also getting a lot of reports of buffer allocation zero.
Here's the detail from the sandboxd out:
mds(68) deny file-write-create /private/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T
Process: mds 
Path: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Metadat a.framework/Versions/A/Support/mds
Load Address: 0x106592000
Version: ??? (???)
Code Type: X86-64 (Native)
Parent Process: launchd 
Date/Time: 2011-08-16 22:45:26.988 -0500
OS Version: Mac OS X 10.7 (11A511)
Report Version: 7
Are you using a username originally created in Tiger and migrated through different versions of OS X?
Yes I am, and I am having these issues alot.
My username was actually created in 10.0.
I migrated through many 10.x's.
When I came to Lion, when I first updated, my user account was not there at all. So I had to add it manually by creating a new user and pointing it at the old user directory. What would that have done?
Oh yeah. I also changed my user's UID in Directory Utility so it would match the one on my laptop and I could access files between the machines without permissions issues. Was that bad to do?
Getting the following errors in console log after I upgraded to 10.8 on a client machine
error message code
sandboxd: () Mail(6449) deny file-write-create /path
I have creted a symbolic link to the location of the mail folders off to another hard drive. Worked fine in 10.7, looks like this is no longer supported.
Mail can't seem to create new folders, or if they are already there the IMAP folders convert to Read-Only
Thanks for the hint: I upgraded to Mountain Lion (10.8.2) today ... since then I had two new "features" (among different others!):
- Mail.app aborted every now and then
- Mails from an Exchange server were "read only" (no remove/no move possible)
Just found this discussion here by googling for "sandboxd ...: Mail(...) deny file-write-unlink .../Posteingang.mbox/".
The directories were actually a symlink from ~/Library/Mail/V2 to a second hard disc since I wanted my external emails on some other disk which worked perfectly well under 10.7 (Lion). However, moving back the folder to the "right" place solved the two issues (at least until now).