"Losing a key employee in a small company is really one of the most difficult situations you’ll have to deal with as an entrepreneur/startup executive. One thing I do not recommend is trying to retain the person who is leaving. If they’ve shown the willingness or desire to leave, you have to let them go. There is no such thing as indentured servitude in startup land and when someone shows that they are mentally out, they should not stick around except to insure a smooth transition."