I have constant problems moving large files in Mountain Lion. When I say large I would say roughly 2GB or larger, which means nearly every iso and vmdk I touch. This can occur moving a file to or from a USB disk, a FW800 disk, a samba share, a netatalk share.
For instance, here is the latest error: "The Finder can't complete the operation because some data in "Fedora-18-x86_64-DVD.iso" can't be read or written. (Error code -36)"
I know the data is not corrupt because I can use rsync to copy this file to the exact same destination and it will succeed, just that finder will fail to copy it. I've also used the same file to install a vm which worked fine as well as moved the file with a USB stick which for no apparent reason succeeded. On top of that when I share out files using SMB from the same Mac and try to move the file from a windows server the connection will hang up halfway through the copy for no apparent reason. Is anyone aware of a larger bug or problem with large files in 10.8?