Question: To make copying quicker from my hard drive to external hard drive and the other way around, I sometimes have several transfers windows together transferring multiple files/folders.
Does this method cause fragmented hard drive and it is better to have 1 transfer instead of multiple?
Answer: In practice, No. Theoretically, Yes.
No, because there are several factors that could cause a file to be fragmented, if you execute one or three copy dialogs at the same time shouldn t matter.
Yes, because it could happen that one file from one dialog only write a file partially and the second dialog write the next file directly after it, causing the first file to be fragmented. However, given how many writes a typical computers executes every day, this could be ignored.
I guess the best solution (if you want to be 100% sure) is simply executing the copy as fast as possible to get the job done fast, and in the night run a defrag cycle.
In case you are running Windows 7 you don t even need to this because it will run DEFRAG once a month anyway.