External drives for Mac Mini....?

I've been using Seagate ext hard drives for a few yrs on my Windows pc and now that I'm new to Mac world, have a Mac Mini. Had a new SEagate with the power base and a Firewire cable that worked fast, and great until the base went out. Returned to Best Buy and they had no others but had similar units with USB3.0 cables. Ever since I've been trying these on my Mac Mini, a lot of the time I can't see all my files in my folders and it even disconnects itself a lot. Lately, the Mini gives me the swirling color wheel and I can't open anything. I'm wondering if the problems are with the 3.0 cables, or compatability with the Seagate drives, or ? I'm no computer geek, and am brand new to Mac. Should I be using a different brand of external drive and a Firewire cable only? Any suggestions are appreciated. Thanks!

I'd suspect that cable, but I have to ask: did you reformat the drive to be compatible with Macs before using it?

You don't say exactly what model Mac mini you have, so there's no way to know if it has USB 3 on it or not. Though I personally prefer FW800, USB 3 should be more than adequate for the uses you've described.

The drive has been working and was pc/Mac formatted already, it said. Just found out that the Mini is 2.0 USB and I'm using 3.0 cables, since I don't have the Firewire option with this power base, until my adapter comes. Is that why its freaking out? Forgive my Mac/pc ignorance.

Normally I'd say no, since USB 3 is designed to drop down to USB 2 gracefully. But I don't know enough about what "USB 3 cables" are (how would it know?), so I'd suggest trying a normal USB cable and see if there are any different results.

If the drive is "mac/pc formatted" what they mean is that it's PC formatted, probably FAT32 for maximum compatibility. If so, this would explain why you can't see files that are over 4GB in size (ie, some videos). If you are going to use this drive with the Mac mini, I'd suggest formatting it for Mac.

Got me a new Firewire cable power base for my Seagate ext drive and though its faster than the USB, I still can't see all my files. I looked at the disk utility for the drive and the format said: Windows NT. So, according to reformat directions I found , emptied the drive and reformatted for Mac . Now I'm trying to copy 255 gb of photos from my older back up drive to the new empty one , but it gets less than halfway through copying and stops. Won't continue. What gives? I'm exhausted trying to figure this out.