I look to any addons past what Microsoft installs. Some install firewalls and more. Such may incur this issue.
In closing, your post ignored the forum tip. No mention of make/model/OS/patches and more. Maybe the forum could see if there is a cure if you told more.
Worth noting is that many owners know nothing about their hardware as to the need for motherboard and USB drivers. Windows is still not a consumer grade OS in spite of all the marketing that tells us otherwise. http://www.usbman.com notes USB issue galore, but I can't narrow it down due to lack of detail in your post.
Best of luck,
I use a USB drive to move files from my computer (W2kPro) to others (W2k....XP).
Often on my computer when I try to "Unplug/Remove" I get a message that the device CANNOT be safely removed.
That comes AFTER I have closed all files/apps on the device.
It hardly ever happens on the "other" computers.
How can I fix this?