Timothy Gootz - 2013-10-24

I recently download the latest 7zip utility for XP so I can archive several folders. After creating the archives I copied them onto an USB hard drive. Later when I tried to open the archives I can only open 2 out of the 3. The archive that will not open gives me an error stating "Invalid or unknown archive format". The size of this archive is little more than 5GB and it contains many sub folders and files of different types. The other 2 archives are much smaller. I have search looking for a reason why or better yet some solution to allow me to read this archive. Any help will be greatly accepted..