Bobbin plays a very crucial role in embroidery - it is the thread which runs under the fabric, creating the knots and keeps the top thread from unraveling -  of course,  the digitizer also needs to  tie in and tie off the first and the last stitch on an embroidery object as well to secure the embroidery.

There are instances when bobbin thread, which is white in color 99% of the times, shows on top of the embroidery and plays spoil sport - so, here are the reasons that you should look at, that could be causing the bobbin thread to show on top.

1. The tension of the top thread is too tight, pulling the bobbin thread more than its supposed to and dragging it above the fabric.

2. The screw located on the bobbin case is loose and is releasing more than required thread.

3. If both of the above reasons have been taken care of and still you face this problem, than reversing the direction in which the bobbin rotates, while feeding the thread, could also help.

Happy Embroidering!