To use X-light as expander for PC, you have to set it as Midi peripheral devices, otherwise the PC employs the internal sounds and re-directs the audio at X-light: the result is that the sound is emitted by X-light, but the expander function is done by the PC and not by X-light (in fact, the MIDI LED on the front doesn’t flash).
Only on the old operating system Windows XP is possible to set X-light as “predefined MIDI peripheral device”.
On the other operating systems, you have to set X-light as MIDI peripheral device, using the different types of software in use (VanBAsco, Hi-Play, QMidi for MAC etc).

These Midi files have been programmed using non-standard DrumKits which are not present among sounds of X-light1. We made an utility for Windows, able to take action on Midi files and convert them in a way to make them compatible. You can download the utility at this link and follow this procedure to install it:
1- Unpack the file in a folder of the desktop
2- Launch the MidiDrumFix program present in the folder
3- The software asks you which files or folders you want to take action on. Among Midi files selected, the utility will change only those recognized with non-standard DrumKits, ignoring others. The files ARE OVERWRITTEN: if you want to maintain the original ones, you have to make a backup copy.

NOTE: this problem exists only for X-light1. On the following versions of the product (X-light2, X-light3 and X-light4), this utility is integrated in the software of the machine and therefore X-light2, X-light3 and X-light4 DON’T NEED THIS SOFTWARE (it is useless).

It doesn’t exist a unique solution for this problem; quite often this depends on an overloaded in the PC at the time when the block happens. Both the audio and the Midi pass through the USB cable of X-light and the Windows driver is made so that, if (even for a moment) it is not able to send audio data, Windows disconnects the peripheral device; the result is that X-light is disconnected from PC (Note: this can happen also when a Midi file is played).
It doesn’t exist a specific treatment, but we can give you guide lines to follow:
1- Connect X-light to the external power supply
2- Update Windows to the last release with Windows Update. Often with the update of the PC’s operating system, the problems are solved
3- Avoid installing many audio sheets on PC you use to play live
4- Do not overload the PC with useless operations during the playing of songs in live performances
5- Control the quality of the USB cable and the goodness of the connector
6- Try to use a powered HUB USB (you find it in electronic shops)

With X-light3 you have two possibilities:
1- Use the Jack-Jack stereo cable of 3,5 mm from the audio output of PC or IPAD to the LINE IN analogical input on the back. The audio is mixed together to the signal coming from Midi
2- Use the USB output selecting X-light3 or X-light4 as audio peripheral devices. To make this, X-light has to be re-programmed in Midi+Audio mode