I just want to add a few comments to this.

First off. Thank you for this forum. I thought I was the only person with this trouble. Seeing this restored my sanity.

Here is some of the specs we are working within.

2k Exchange enviroment.
Clients

PC XP Pro SP2
MAC OS X 10.4.11

The PCs are useing Office 2003 SP3
The Macs are using Office 2004 W/ patched up to 11.4.1

People have mentioned a number of files having troubles.
I can confirm we are having troubles with jpgs and eps files.

The jpgs needed to be created from PS. Jpegs from a digital camera were not affected in our tests.

We do not use OWA so we sent files to a mailbox on the server.
We then tested downloading and opening the files on each of the clients. We noted that when downloaded from Outlook 2003 the file's size increased and when viewed in WordPad you can see the data tacked onto the beginning of the file. Downloading through and Entourage client did not effect the file.
We too determined patch KB945432 was involved and were succesful removing the patch to restore proper transmission of the effected files on our test machines.

We are not currently goingto remove teh patch from the workstation be cause we have found a few interim solutions to hold us over.
1. Changing the encodeing in Entourage from AppleDouble to MIME/Base64 allows the files to pass. The mac user gets a warning about potentially removed apple data. This has yet to be a factor.
2. Compress attachments.
3. Edit the saved file in Wordpad to remove the offending data added to the files.

The Example below is the first few lines of a good file viewed in Wordpad.
*************************************
%!PS-Adobe-3.1 EPSF-3.0
%ADO_DSC_Encoding: MacOS Roman
%%Title: AbingtonPAL_LCEM 08-0268.eps
%%Creator: Adobe Illustrator(R) 12
%%AI8_CreatorVersion: 12.0.1
%AI9_PrintingDataBegin
**************************************

The file corrupted adds characters to the first line.
If you remove these the file can be opened.

4. Finally just have the PC recipient forward themail to a mac user to open.

I'll gladly add anything II can if there are any questions.
I hope i've coverd all of the points.

Matt