I've used the FM transmitter a few times before and it worked perfectly. Suddenly, (today) every time I try to activate it or change the settings, the N900 waits about ~20 seconds then a message box shows up that says simply "Unable to use FM transmitter". This happens if I try to access it though media player or through the settings tool.

I've tried rebooting, switching off/on and even tried removing the battery for a while. Nothing has helped. Does this mean my N900 has a hardware problem, or is there some setting somewhere that can fix this?

If anyone has seen this or can offer any info or suggestions I'd really appreciate it!

Welcome to the forum!
Is USB (charging mode) is connected, or anything else worth to mention?

The same happened also to me :-(

It happens even, when the boot is done without any cable...

What helps: installing "gainroot", "sudo gainroot",killing the fmtxd with "killall fmtxd", and then restarting the fmtxd:
"fmtxd -d". Then it works!

(but needs to be repeated after each reboot, if the "fm transmitter" is to be used again...)

Happened to me also. My transmitter got stuck ON! Every time I unckecked the tickbox "FM transmitter on" and hit 'Save', I'd get the error message "Unable to use FM transmitter" and the thing would be left on.

Although when I say 'on', the N900 showed that it was on but I didn't pick anything up on my radio.

Reboot fixed it though. What is this, Windows?

Nope - because you could have simply restarted the daemon instead of rebooting. Windows generally doesnt give you that option. Remember Linux is about control, whether you exercise that control is up to you.

i had a simliar issue too. but then after cleaning out some of the softare i downloaded it fixed itself. though i am not sure "which" software it was. i should have tried it inbetween each uninstall, but didnt think about it at the time.

off subject, but i cant wait for "good" apps to start showing up.

also, i noticed that you can only use the transmitter for music, not calls. which defeats the purpose for me to not use my current motorola t505 to transmit to FM. :/

but cool thing is that it transmitts NOKIA to my audi's digital tuner.

check your software.

OK, I was more frustrated than troll back there. Now (after Jan's post) I know that fmtxd is the relevant daemon, and as a linux user that means something to me. I don't think that Joe Smartphone will appreciate the 'simple' superiority of Linux.

I will try to get the error reproducible for a bug report.