Dear Michael Arrigo
Thank you for posting in the Microsoft community. The issue about your external USB hard disk not being readable is actually very complicated. We'll walk you through the steps to troubleshoot your problem.
1.1 Hardware issues, usually external hard disk has independent power supply and rely on USB power supply two modes, if your hard disk box has independent power supply, then you can skip this step, if your hard disk does not have independent power supply, we recommend that you replace the USB interface to USB3.0 interface, his power supply is more stable.
1.2 If you have other computers, you can try to insert the external hard disk into other computers to test whether it is a hardware problem of the hard disk itself.
- Permission problems, you can check whether the computer has installed three-way anti-virus software, some anti-virus software will prohibit the reading of the external USB hard disk. If your laptop is a HP notebook, HP security center will also have similar settings on the external hard disk access need to be opened.
3.1 Driver issues, some external hard disk enclosure can not be used directly through USB, you need to install the hard disk enclosure separate driver and firmware to be able to use normally, if it is convenient if you can tell your hard disk enclosure model, so that we can further inquiry.
3.2 Computer driver problem, you can try to enter the official website of your computer's motherboard manufacturer to update the chipset driver, which will also help to solve your problem.
4.System problem, you can refer to the following solution, update your WINDOWS 10 to the latest version, it will fix your system level problem and install some stable version of drivers.
First of all it is recommended that you backup your important personal data just in case.
Regarding your problem it is recommended that you try the following steps for a WINDOWS repair installation:
Download Windows 10 (microsoft.com)
Select Create Windows 10 Installation Media - Download - Execute - Select Accept Terms - Select Make Media Tools for Another Computer - DVD ISO file - Select Save to Desktop - Open WINDOWS.ISO file - Run SETUP.EXE. Wait for WINDOWS Update Repair to complete.
Looking forward to your further feedback.
I wish you all the best.
Best Wish
Shawn Z | Microsoft Community Support Specialist