Well. I had it set for a default tone but it would play a mp3 from my files that had never been set. I deleted that song and tried to default it again only for no sound. My text and outside email account works fine it only my gmail that does not /c:
I have always (with Droid 1 before my X2) had custom ringtone files that I have typically kept on my SD card. With the X2 I had a lot of problems with them staying intact. I found that if I moved files to or from either SD Card, it would remove the sound files from the app they were applied to. My alarm clock sound kept changing. Try setting it to one of the internal stock ringtones and see if that stops it. Or put your custom ringtone file in the System/media/audio folder.
Ok weird! I linked my phone into the pc to copy some music to my pc folder after unplugging it one of my notification sounds is playing for my gmail now. Totally confused by this lol thanks for your help