Disk eject

Hello,

I use a portable external hdd on a daily basis.
I eject it in the morning, I go to my job with it, I go back at home in the evening.
So, each day I eject it at least once.
Since I upgraded to avast 5, I can’t eject it, being in use by the process called AvastUI.exe.
I couldn’t find any way to convince this process to ‘free’ it.
Is there any known solution to that?

What is on that drive? I suppose avast! is installed elsewhere, is it?

Of course it is installed elsewhere, on the regular path C:\Program Files\avast5 etc…