well if the partition was made and you did not catch it may be the cause but you should see that in your disk management if there are more then one on the disk. also if windows was allowed to do this when it was fresh installed it will a lot x-amount of drive space for its self and it may have glitch and took way too much on it own [I have seen this] most time s it takes about 32gb. but when you do a fresh install on a new drive and you want all the drive space you can get you got to set up the partition to the size of the drive that's stated during preinstall and that can keep windows to around 19gb and the rest is yours..
well if the partition was made and you did not catch it may be the cause but you should see that in your disk management if there are more then one on the disk. also if windows was allowed to do this when it was fresh installed it will a lot x-amount of drive space for its self and it may have glitch and took way too much on it own [I have seen this] most time s it takes about 32gb. but when you do a fresh install on a new drive and you want all the drive space you can get you got to set up the partition to the size of the drive that's stated during preinstall and that can keep windows to around 19gb and the rest is yours..