When you use the "Create Archive" function on your Mac (to create a zip file), hidden files are inserted into the zip archive. While you cannot see these files on your mac, PC users will be able to see files and folders that would be hidden on the Mac: The ".DS_Store" file and "__MACOSX" folder.
Not only can these files and folders confuse your end-user - but they can also confound downstream processing on PC where the end-user has automated extraction for zip files, resulting in a failed extraction of the zip file. For example, if the entity to whom you are sending the zip file uses automated processing to unzip the file, their software may be unable to process zip archives created on your mac computer. The solution is our Zip Mac Files for the PC utility... a simple, lightweight drag and drop application that keeps Mac and PC users talking.
This application will create zip files that you can send to PC users with no problems.