Can't Open USB Devices

Hi Robert,

is the drive detected as having FAT32 or NTFS file system in Windows Disk Management? Do a right click on My Computer - Manage - Disk Management. See if the connected USB stick has a detected file system (NTFS or FAT32). If yes then your problem is in access rights. You need to take ownership of the drive.
If not - then the problem is in file system of these drives. Connect the drive to a PC where you can work with it - and check the partitions on the drive with CHKDSK x:/f via command line where X: is the drive letter of a USB drive.

There is also a third possible reason of this problem - the USB interface of your "problem" machine does not give enough power to the drive. Thus you need to try connecting the drive via powered USB hub.

turn off the UAC and use windows explorer to explore files and then try to open the flash drive

All my flash drives are seen as FAT32 but if I try to take ownership I get the access denied message.

Turning off UAC did not help. Same problem.

I do have one flash drive that is NTFS but I have the same issues with it.

Then you need to check with a powered USB hub. Have you tried them on all USB connectors?
As a test you can uninstall USB interface via Device Manager - then restart and let the driver install again. After that check if the problem is gone.

I have the same issue using a powered USB hard drive enclosure. I get the same error when I try to access the data but I can run hard drive diagnostics on it. This is a new problem that just started this morning and that is why I don't understand what could have possibly happened to cause this.

You can roll back the system to restore point with hope that it will fix the problem.
Try to remove USB devices from Device Manager (uninstall USB concentrator), reboot and let it teinstall.
Amother idea which came to my mind - will the USB drives work if the machine is booted from a WinPE CD or from Linux distro?

it can be caused by manufacturer software , see the solution for HP here :  It was the pre-installed "HP Device Manager" causing the denied access
http://h30434.www3.hp.com/t5/Notebook-Operating-Systems-and-Software/Access-Denied-on-USB-drives/td-p/3662944
if you have similar software - uninstall it - or call lenovo in !

OK, here is what I have tried over the past week or so -  I needed to make a bootable USB stick so I used diskpart to clean and format the USB drive and I had no problem doing that. I also had no problem extracting files to the drive. But once I removed the drive and reinstalled it I got the drive not accessible message.
I tried changing the permissions (because I thought being inaccessible could be a rights issue) but when I try changing permissions or changing the owner I get an "access denied" message.
The drive appears in Computer management and the size is correct but I can't do anything with it.
Any more suggestions?

What is it like on other machines?

Also look at Rufus https://rufus.akeo.ie/ to set up your USB sticks.

try safely remove to acces the drives http://safelyremove.com/?pid=1

try also this :
right click on the START icon, select explore all users, navigate to your USB stick in the left column, and you should be able to open it.
 alternatively go to RUN type D: and press enter.

All of these USB sticks work just fine in other machines and they all worked in this one until recently. I did not use Rufus because I am not having any problem creating a bootable USB device and I do not want to format any of these flash drives.
If I right click on Start I do not have the "explore all users" option and if go to RUN type D: and press enter, I still get the drive not accessible error. If  I try to run the safely remove app I get an endpoint security personal policy alert - Data Protection Alert - "PSG protected a file from being changed"

That did the trick. I think there is an updated version that will fix the problem.

tx for feedback - and i'm happy to be able to help