cmgadent.exe not letting me safely remove external hard drive

So if I try to eject the drive from the notification area in Windows 10, I get the message that the drive is being used by another device.
So I downloaded and installed “USB Safely Remove” and it tells me that this process using the drive is “cmdagent.exe”

I have HIPS, Viruscope, web filitering and auto containment disabled. I just use the firewall.

Can anyone please help me out?

It’s a long time ‘bug’ where if the drive is plugged in after startup, everything works as intended. If already plugged in on startup, then this problem can arise

https://forums.comodo.com/defense-sandbox-help-cis/comodo-cis-10-prevents-ejection-of-usb-mass-storage-devices-leads-to-corruption-t120751.0.html;msg867241#msg867241

Thanks @ploget

Very interesting that this have never been addressed.
I guess I’ll just have to purchase “usb safely remove”, even though restarting the computer seems to work I feel uneasy doing that.

It goes even deeper than cmdagent.exe. Windows also is known to block it. I once did an online search on this and found various topics about it. It turns out Windows also has a way of interfering with safely removing external drives. Linux is said to always facilitate safe removal.