It is very frustrating to buy a USB portable hard drive of large capacity and find that it does not work well on certain computers because these do not provide enough power through its USB ports. This happened with USB 2.0 but it was aggravated by the incorporation of USB 3.0 interface. One trick that has helped me many times is to always have short cables.
We all know that electrical current (amperage) decreases with the quality of the wiring and the distance, so always keep handy a high quality shorter cable and you will see the difference, so your USB hard disk will have almost full compatibility, even on older machines. Some drives have bifurcated cables, to add the power of two connectors, but they are usually a nuisance and they eat up two ports, which in many cases they are not even close one from the other.
As you see, the difference between a normal cable, a drive or external drive, is that the shorter it is, the more evident that it results in better performances on machines with power problems.
The standard cable that usually comes with USB drives is around 50-60cm long. Reducing its size by half allows us to maintain much more amperage to power the drive. My advice: get some cable of about 30cm, that is affordable and that can improve the portability of your drive. It seems silly, but not always bigger is better.