[AT&T Samsung Galaxy Note I717] littlewierdo:
It has to do with the bizarre way Windows handles drivers.

EVERY phone state has to have a different 'driver' installed, although technically, it is using the same driver for each phone state..

The Note actually has five states, Download mode (this is the mode you would put your phone into to 'Odin' anything to it), Recovery mode (Clockwork recovery menu), Debugging mode (turn on USB Debugging) - also known as ADB mode, Mass Storage, and Wifi Direct (useful for connecting to your PC's files or public files on your phone using your PC - requires the PC to have wireless capability). Due to the way plug and play works, any device connected to your PC must put out a 'ping' to tell the OS what it is (a device name). Samsung has opted to really confuse everything by reporting a different device name for all these different states rather than doing what most devices do, a recovery mode and a mass storage mode (two states instead of the 5 Samsung is using).

Installing the samsung note driver via kies is sufficient to cover all the different states (windows just duplicates the driver for each new state it has not detected previously) but in order to cover every state the phone can possibly be in, you have to plug in the phone while the phone is in that state (ie. plugging it in with USB debugging on will install the drivers for ADB mode). One other note, just in case you are getting the brilliant idea to go ahead and -pre-install all of these different states, it has to be done for each USB port (each state) and Windows tends to remove unused drivers after a short period of time (if you havent put your phone in download mode and plugged in to your PC in awhile, chances are, Windows will have to reinstall the driver for this state again). This is why in the instructions I listed, I explain putting the phone into mass storage mode and then back into ADB mode - this forces windows to install the drivers for each state.

For those still having trouble with this, reboot your PC and try the instructions again. Pay very close attention to the system tray (the icons by your clock in the lower right corner - typically unless you moved your start menu).

MAKE SURE that windows FINISHES installing the driver for mass storage BEFORE you switch to ADB mode or you will have problems. BE PATIENT! Put your phone in mass storage and go get a coffee, do a cross word puzzle, take a shower, whatever. It takes anywhere between 30 seconds to 5 minutes to install the driver and if you interrupt the process, things become wonky until you reboot.

There will be an icon by the clock that is animated while the driver is installing (click it and it will tell you it is installing the driver). When it isnt animated, clicking it will tell you that windows finished installing the driver. DONT RELY ON THE ANIMATION! Click the icon and be sure it has installed.

Also, you cannot have Kies running while Windows is installing the driver. If you do, windows will correctly install the driver but Kies will never detect the phone. It is possible that shutting Kies down and restarting it (and repeating the steps I mentioned to get Kies to connect) may correct the issue but most likely, it will require a reboot and then you will have to run thru the steps I outlined again to get it to connect properly.

This is a combination of Windows and Samsung both. Windows could handle this so much better, Samsung could have reported the device as two possibilities instead of 5. But, what can I say, One company is Korean and one is American and they each like to do things their own way.