I was recently attempting to copy over some data from my external USB Hard Drive to my local computer and I noticed that Windows File Copy would either hang Windows Explorer or fail in the midst of a Windows File Copy.
After being frustrated with several Windows File Copy attempts, I decided to open up my favorite tool—Scooter Software’s Beyond Compare (http://scootersoftware.com/download.php) and attempted the same Copy operation in Beyond Compare instead.
After a few minutes of attempting the file copy within Beyond Compare, I soon discovered that there was a Cyclic Redundancy Check error on my disk. Fortunately, Beyond Compare is capable of ignoring those Cyclic Redundancy Check error messages and copying content from the hard drive file system which do not contain those CRC errors!!
As you can probably guess, Windows File Copy available through Windows Explorer will simply fail out completely when you encounter Cyclic Redundancy Check error and will not allow you to copy any other file content items.
Therefore, for the most reliable file copies, I would highly recommend using a 3rd party tool such as Beyond Compare as opposed to the standard Windows File Copy mechanism.