There are many things which are usually ignored, And the question on naming of default drive in Windows is one of them. It could be anything if it had to be C as it does not follow any order. Logically A should be the default drive. Then why? why did Windows do this? Actually the reason is something historical. And it is related to the classic floppy drives . Before hard disks became standard(1980), floppy disks were used for booting the computers. These were available in two sizes at that time: 5 1/4 ” and 3 1/2?. Those two floppy disk drives were labelled as Local Disk (A) and Local Disk (B). After the invention of Hard disk, floppy disk of size 8 inch came into existence. The hard disk drive was named C. Once hard disks became standard and floppy disks became obsolete, the drive names A and B vanished. As a result , drives other than default drive (C) labelled as D, E etc. DVD drive and USB drive are labelled as F, G and so on. This is the answer of our question. Despite of all this, you can rename your default it to whatever letter you want( if no other drive is present with same alphabet as its name) if you have administrative rights. If you have one such question that you think has been ignored for a long time and should be searched for answers, you can post it here in the comments.