I also tried including the disk folder (E:) as you suggested, but still, Windows did not allow me to eject the hard disk. The only solution I have for this is to restart the laptop, but that is not a solution. Moreover, I am concern about what could happen
with the data in the hard disk, as although I restart the computer I still have doubts if some data might be corrupted.
@Nekovolta,
The exclusion list is not effective immediately, it requires a reboot to be activated.
It only works assuming that device letter(s) are the same when you insert the external drive(s).
Also it will only be effective if MsMpEng.exe is the cause of the problem.
You will need to check the Event Viewer, Windows Logs, System and see what the message for error 225 shows.
There could be other programs or processes that prevent the ejection, in that case the exclusion from defender will not help.
It works fine for me on 6 machines at Build 19042.662 and also Development Builds 20262.1010.
I've been using the exclusion for several months even before the defender platform was updated from 4.18.2009.7-0 to 4.18.2010.7-0.
The application \Device\HarddiskVolume3\ProgramData\Microsoft\Windows Defender\Platform\4.18.2010.7-0**MsMpEng.exe with process id 4380 stopped the removal or ejection**for the device .....