Windows USB Can Never Eject Without Error?

I get impatient at times and try to Eject a USB device without waiting for the Operating System to agree, says it's not yet ready. And it is not only Win10 but I got it on several earlier versions of Windows, Mac OS X [now known as macOS Sierra] and a couple of versions of Linux. There was some help with Windows 98 SE/Second Edition when support for USB 2.0 drivers were included but still run into the issue when the OS is not ready, have to just wait a bit and try again. I have gotten some errors when I was impatient and did learn from that. It's also possible that Windows isn't the only culprit, could be some program, even though appearing to be closed, has actually left something running in the background. It's a lot like some closed programs don't properly remove themselves or their data from RAM.

I have this actually happen often, especially after I get done saving word documents to my flash drive that Windows doesn't think it's finished saving the file.

I've had to close all open programs that was using the flash drive before Windows would let me safely eject it. I've had this problem since Vista and I guarantee others have too. Sometimes​ you just have to be patient. Make sure you close all open programs before ejecting.

One of these may be in use:
Application
file (open document, music, video)
Sometimes it is the antivirus scanning the files on the drive.
Open task manager to view what is still in use.
Close whatever you can so you no longer get the message.
Over time there is a risk of damage to the files if the message is ignored. It just takes 1 time out of 100 to make it painful.
Turning off or rebooting the computer is another option that can be used to safely disconnect the drive.

Bastet said:

It also may be your anti virus software running a scan on the drive which is preventing safe eject. Give it a few moments then it should give the OK.

Hi I dont have any antivrus except for Malware bytes Trial.

And it doesnt run unless I specifically make it

----
I also waited 10 minutes and still no good, I dont think I can wait more than ten minutes every time i need to unplug a external drive...

Place your computer in clean boot and see if there is an impact on performance:
https://support.microsoft.com/en-us/...oot-in-windows
How to perform a Clean Boot in Windows 10 - TechNet Articles - United States (English) - TechNet Wiki

If there is increase performance in clean boot then you may be able to find the application that is delaying the safe removal of the drive.

To make sure I understand this: the issue happens every now and then on both your Win10 & Win7 computers.
--- I am not a fan of removing USB devices frequently, actually not more than once, maybe twice.
--- I’ve seen too many people run into lost/corrupted data too many times
At this point when it happens again, instead of removing the USB device, click on shut down.
--- There should be a message indicating what the reason is on Win10, Win7 I don’t recall.
--- Allow the forced shutdown after knowing what the message informs what’s going on if it's possible to do.

Moving on
Since you have the same issue on 2 computers, ensure that each and every time, the external hard drive USB connected drive is always the same for each computer, for example drive E.
--- Since you have 2 computers, the process is dependent on the original drive for each computer and maybe each one is different from each other.
--- The USB hub has multiple connections, depending on how they are used, the normal drive connection can change.
--- That can be fixed but it needs to be known whether or that might be happening.

You are using the Malwarebytes free trial for your antimalware protection.
--- You mention you run it manually
--- Malwarebytes free trial is supposed to run in real time: is it past the 14-day free trial period?
--- If so, the full benefits of Malwarebytes are not use anymore even though you can use it manually

If you don’t have a real-time security program in use
Windows Defender should be running automatically on the Win10 computer.
--- Check Security and Maintenance and see what it reports for Virus Protection
On your Win7 computer, it would be a good idea to use Microsoft Security Essentials.
--- Check Action Center and see what it reports for Virus Protection