Saving file problem in Photoshop CS

When I'm trying to "save file" command after scanning is complete, file became corrupted, unless extension .psd is added at the end of "file name" in the first line.
Second line in "save" dialog box, set to "psd*pdd" format. Still I have to type-in extension .psd or it not working. I call tech support but they don't know why it doing that. Their suggetion was to put extension .psd on the end of a file name. It is abnormal.
Any better idea?

Simon

Simon ... Dunno about CS but I had a mess with PS 7.0 trying to save scanned files from an Epson 2450 USB ... solution was to simply not turn on the scanner until AFTER PS was fully open and ready ... In my case all the save problems went away .. easy enuff to try .. Rgds.

Thank you Henry.
I will try