USB flash drives takes long time to show up in explorer

Hi,
I'm running windows 8.1 x64. When I insert a usb flash drive into my PC, it takes maybe over 2 minutes before windows "finds" it and has it appear in windows explorer. I have no idea what to do about this. I have the latest BIOS for my motherboard and I don't think there are any specific usb drivers to install.

thanks

I assume you tried different ports and different sticks and have gotten the same results?

Also System Specs will likely be helpful

Yes, I've tried other ports and same behaviour. I just tried it again and it took 6min to show up. However, I found another usb flash drive and it worked fine.

The flash drive is a Lexar 8GB, usb2 I think.
I just remembered: I had previously used this usb flash drive as a ms-dos bootable drive. I've formatted it since. Disk manager only sees one FAT32 partition (the one I formatted).