Be aware that some actions, including SendKeys, can turn numlock off - even if the keys being sent are NOT to turn numlock off. Some api calls can mess with num lock too. I have a simple vba code in an Excel workbook that maximizes excel when it opens and sets the focus - and it turns off my num lock for reasons I cannot determine. I hesitate to offer the "undocumented/unpredictable" answer, but I do feel that num lock turning off sorta falls in this category sometimes.