TeraCopy is a free program that bypasses the windows shell to take full advantage of the drive technologies on offer to optimize your file transfers. It speeds up the file transfers, then it can pause and resume file transfers perfectly. It avoids interfering with other Windows processes, for example. When two identically named files are encountered, you can also configure the program to behave a certain way by default (such as renaming one of the files or not overwriting).
[advt]The program also intelligently handles file errors: it will attempt to re-copy the file a number of times before moving on to the next one instead of throwing a hissy fit and abandoning the entire process. Again, you control how the program handles these errors, and if failures are encountered, It will list them after the file transfer is complete, giving you options to deal with them. You can even test and verify files in both pre- and post-transfer, adding an extra layer of protection to important files and folders.