COM3 error

I have a Mega 2560 and when ever I try to download a file it says "serial port 'COM3' not found". Whats my problem I have the right board selected and I think the right programmer.

What operating system type and version?

Windows 7 home premium, 64 bit.
Thanks for the reply :slight_smile:

I also have these problems with Win7 x64. I have to actually restart my computer for it to recognize it again...

I'm having the same issues with win7/x64, but for me it works just unplugging and plugging back in.

Happens every other time I plug the Arduino in. (Arduino Uno)

Yayaya it is working

actually it seems to vary with what USB port i'm using how often this occurs.