EOS Rebel XTi 400D flash not popping up - Canon EOS 400D / Rebel XTi Digital Camera

spray a very very small amount of WD40 on the hings of pop up flash (use the thin RED spray tube)

This is a problem known by Canon, you will have to have it serviced.

Be aware that the built in flash does not pop up automatically in all picture modes. Try it when in the different modes (on the mode dial) and see what I mean. Does it popo up when manually opened ?, (small button on front left hand side of the viewing pentaprism/flash housing.)

Here's how to do it:

Go to this page: Canon Digital Rebel XTi

Click Drivers & Downloads, scroll all the way to the bottom, and click on the PDF link as shown.

EOS DIGITAL REBEL XTi / EOS 400D
DIGITAL Instruction Manual
EOSDRXTi400DIM-EN.pdf

If the flash fires a full charge(eg. in a dark environment) then this message will appear whilst it recharges. If the message appears all the time and you cannot take a photo there is most likely a problem. Try taking some pictures without the flash card to eliminate that first.

EOS 400D / Rebel XTi Digital Camera
EOS 400D/Rebel XTi doesn't have live view function, so you cannot see the picture you are taking.

sounds like a problem with the card
what card are you using?

try formatting it. or try a different (maybe faster) card.

maybe it is dirty ... try cleaning it and the area around it ...

It appears that the small hook that holds the flash down is not latching properly and perhaps needs replacement. If your camera is still under warranty, call Canon Customer care. Even if the warranty has just expired (like 1 or 2 months), they generally honor it and get the service done free of cost.

I made the mistake of putting ahotshoe protector from my old camera on the new EOS 400D. It stopped the flash from popping up. I took it off and things now work.