File permissions with Mac and Windows file share

Elgininfo
Elgininfo used Ask the Experts™
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We have one Mac user on our Windows 2003 network.  When our Mac user opens a Word file fron a drive on our windows network, it creates a 4 kb file with the name " ._filename".  
The file is then marked Read-Only for all of our Windows users except for Domain Admins.
Why does the Mac lock files and change permissions for Windows users.  Is there a setting or permissions we can change on his Mac to prevent this from happening.  Or is there another solution to this?
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Commented:
They are called resource forks and can only be seen by windows users not the mac users. Here is some information about them. http://en.wikipedia.org/wiki/Resource_fork. You can remove them on the mac side using something like this http://zeroonetwenty.com/blueharvest/ unfortunately they are created programmatically. I am sure you can script it to be recursively moved through windows.

Author

Commented:
The Blueharvest worked great to delete the .DS_Store files. But the file permissions still dont make any sense. The user is the only Mac user. He is not on our domain but goes to our file server using his network sersources. Obviously his permissions come from Active directory. When he makes changes to a file the users on our domain get ReadOnly on those files except for us domain admins. Our users have modify permission on those files but some how this Mac users is over riding the permissions. How is it possible?

Commented:
You said he is not on the domain but that his permission come from active directory, correct. They could come from the local computer ntfs permissions or the hidden shares available in windows 2k3 servers by default. Currently, Mac OS X does support resource forks on Windows SMB shares by creating a hidden file in the same directory with the data fork file, with the characters "._" at the beginning of the file name. However, this may be annoying for some users, especially because some Windows power users always keep hidden files visible. Besides, Windows does not treat those files correctly as the file itself is moved or removed.  
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Author

Commented:
Let me frame this in another way. The user is on our domain his laptop is not. In other words when he plugs his laptop on our network he uses his AD credential to sign on to the fileshare server.
My question is why does the file lock in ReadOnly even when he has closed it.

Commented:
Windows file system(NTFS, FAT) does know how to handle files of the wrong format designed for Macintosh file systems(MFS, HFS and HFS Plus) and uses byte range locks to lock it as read only. Essentially the resource fork is being created in a format with special characters that windows does not like ? [ ] / \ = + < > : ; " , thus the resource forks become locked to Windows clients but accessible by mac clients. Check other mac clients accessing the share.

Author

Commented:
We have just this one user.Since there is not easy to resolve the file lock issue we have tried a work around and it seems to be working for now.
Thanks for you input and help on this matter.

Author

Commented:
Installing blueharvest helped us to clean up our directory of all the ._files.
It did not resolve the issue of files being saved as ReadOnly.

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