Before I go into all this, this problem absolutely has nothing to do with front or back USB ports on your Xbox. They are identical, absolutely the same, and whoever is trying to blame this problem on front ports is wrong. I've tried all of them with exactly the same result. The only problem is some cables can't transfer all the info Xbox needs them to transfer, that's all there is to it, period.
I finally fixed my problem with Xbox One S not recognizing external HDD as External Storage for Games and Apps, but only as Media Storage.
Of course my drive met all the Microsoft's requirements. External Drive is USB 3.0, and 1Tb in size, Western Digital My Passport. Still I was never able to get Xbox recognize it as an external storage for Games and Apps. It would always be recognized as Media Storage only. I've tried Hard Restart of my Xbox, I've tried Factory Reset, numerous times erasing volume on my external HDD, trying to use it without any partitions on it in hope that Xbox will offer to format it. Tried with partitions on it, formatted as NTFS, as well as FAT32. It never happened, not once I saw that FORMAT option. I also tried changing the type of the drive from MBR (master boot record) to GPT (GUID partition table). I even used DISKPART (diskpart - list disk - select disk # - online disk - clean all) in hope my Xbox One S would finally properly recognize it as external storage. Nothing helped, absolutely nothing. Followed numerous different suggestions from all kinds of MS and XBox forums to no avail.
People blaming new Xbox One S, blaming Microsoft, blaming new Xbox One Experience OS, and what not... absolutely had nothing to do with Xbox hardware or software. It's simple hardware incompatibility between Xbox One S (possibly Xbox One too), and different types of Hard Drives and particularly, as it can be seen from my video, different types of USB 3.0 compatible cables.
I had original, official WD cable that came with WD My Passport, and while it works perfectly fine on PC and Mac, something is going on when it's attached to Xbox One. I've replaced it with another cable, and instantly my XBox would recognize any HDD I would connect to it. Something is about that cable and I'd love if someone more experienced (possibly from Microsoft), could look into it. Video is on a longer side, but I wanted to show what exactly is happening when switching those two USB cables, so people can understand this better.
I am not claiming this will solve every single person's problem with Xbox One/One S not working properly with certain external Hard Drives, but for sure it solved mine. After numerous attempts to solve it, using tens of different methods and suggestions I could find all over the internet, I wasn't able to get this resolved.
I simply tried the simplest possible thing, and that's ruling out the faulty cable. I know, I should have tried that first, but like many of us I failed and checked that last, duh!
Live and learn...
Just wanted to clarify something... this original WD USB cable that came with My Passport 1Tb, is not actually faulty/defective. It works perfectly fine when used on PC/Mac. There is simply something about how it sends/receives data when connected to Xbox One S (possibly Xbox One too). It would be good if Microsoft/Xbox technicians could look into this matter a little deeper.
Again, it will not solve everyone's problem, but I am sure there is many of us out there who never even thought this could be a culprit of all these problems. Well, for me it was.
Hope this could help someone experiencing same annoyance. Nothing is wrong with Xbox One guys, nothing is wrong with Xbox One Experience. It's a simple hardware incompatibility, that's all.
This is the cable that worked with my Xbox One and the external HDD, with all markings on it: http://imgur.com/a/LKMod , and this is the $10 CAD box that contained HD enclosure and that same cable (that works perfectly fine on my end, the one in the video that works): http://i.imgur.com/Z4twtwr.jpg - again, no hard drive inside, just HD enclosure and the cable. As long as you get cable with those markings on it (as in the photo I posted), it should work fine. Cheap cables are much thinner, and most of them have no markings at all." - so, all you basically need is the cable and when you're searching for one, make sure it has those markings like the one in the photos I posted link for above. Truth be told, I can't tell for sure how to search for the right cable, it could be hit-and-miss.
Recording and Edit: Seiishu
Audio: "Viscid Vibes" by Seiishu
Lens: Rokinon 12mm NCS CS MFT