My USB 3.0 External HDD cannot be recognized

When you say "the drives on Device Manager seem to be working fine", does that mean you can see your HDD listed there but it simply doesn't appear in This PC?  Or does the hard drive not appear in Device Manager?  Do you hear the standard "device attached" sound play when you connect the drive?  If you do not and the HDD doesn't appear at all in Device Manager, the 7577 has 3x USB-A ports.  Are you saying that your external HDD is not recognized in any of them even though other USB 2.0 devices work fine in all of them?  Do you have any other devices that support USB 3.0 that you can test?

Thank you very much for your insterest and sorry for being a little bit too late to reply.

What I mean that the usb drivers look ok . When I plug my HDD, I cannot hear the standard beep nor see it in the device manager. However, I can feel the that the HDD is powered up when I touch.

Now, I managed to get it work but inconsistently. Which means that it works but not all the time. Sometimes I have to disconnect and reconnect few times or try different ports until it work.

The last thing I've tried was to use an usb 2.0 extension cable which worked perfectly with no problems. However, l'm afraid that data transfer speed will drop to usb 2.0 standard speed.

Do you have any advice please ?

No I didn't try that. However, I can confirm that the HDD with the same cable works perfectly on several other PCs and Laptops and I've never experienced any issue with it. It also worth to be mentioned that the 3.1 USB port on the left side of the laptop "the one with PowerShare capability" recognize the HDD much better than the other two on the right side. But again, when using a 2.0 USB devices or the 3.0 USB HDD with the 2.0 extension cable I don't have absolute no issue with any of the ports. 

Do you still think that trying another cable would help ?

The fact that USB 2.0 devices and USB 3.0 devices that use USB 2.0 cables both work in a USB 3.0 port doesn't really mean anything.  Again, USB 2.0 data pins and USB 3.0 data pins are completely separate, so it's entirely possible for USB 2.0 to work while USB 3.0 does not.  My theory behind the cable replacement suggestion is that the USB 3.0 pins in the cable you're using and the USB 3.0 pins in at least some of the ports in your system may be on opposite extremes of manufacturing tolerances for placement.  That could explain why that drive and USB 3.0 cable work fine in another system and could even explain why other USB 3.0 devices work fine in all of your system's ports if you've tested any others, while still explaining why that specific cable doesn't work well with certain specific ports in your system.  Incidentally, have you tested any other USB 3.0 devices with your system to see whether they work reliably and run at USB 3.0 speeds?  I asked that question earlier and you never answered it.

Dear jphughan,

Thank you very much for your help. I just tried another usb 3.0 cable and it worked perfectly without any issues on all ports. 

Unfortunately, I didn't have any other usb 3.0 devices to try. and with the cable working on other PCs I didn't really think that the cable could be the problem.

Again, thank you very much for your valuable advice. You are a champion.

my dell does the same thing .hands down the most unreliable laptop I've  ever seen and i handle thousands of client laptops  a year