Pop-up flash not working

[Brachytron]

Hi. Since using my new 430EXII flash in anger, I appear not to be able to use the pop-up flash on my 40D (clearly not at the same time in case that's what you were thinking!). The camera seems to think that the 430EXII is still attached and therefore wont pop up the flash. Anyone found this before and know of a solution? Thanks

 

[andrewc]

there is a microswitch on the hotshoe which is possibly stuck down, fooling the camera into thinking the external flash is fitted