When I'm at home, my Desire automatically connects to my wireless network. However, if I receive or attempt to send and MMS, it doesn't automatically switch to HSDPA in order to send or retrieve the MMS. If I'm sending an MMS I will receive lots of "generic network failure" messages as it repeatedly tries to send it. If I'm receiving an MMS, I will have to download it manually rather than it downloading automatically. If I'm connected via mobile data then I don't encounter any of the problems above. Also, if I turn off my WiFi when sending or receiving an MMS, it works without issue. It seems to make up its own mind as to whether it will automatically switch to mobile data to send or retrieve the message, as it has worked fine previously. It's very hit and miss. Can anybody shed any light? Has anybody experienced similar? Edit: I'm on T-Mobile in the UK.