A colleague of mine mentioned he thinks CHKDSK, since it's so old, probably doesn't support very large target volumes. For example, if you wanted to run CHKDSK on a single, super large volume like say, a 16TB external, you would need to turn to alternative tools at that point.
The Microsoft documentation on CHKDSK is pretty vague. Many of the parameter descriptions leave much to be desired, but that's a whole other issue. I'm just wondering, is there a size limit and if so, what is it?