iPhone4 & microphone - recording unavailable

[artsie-girl]

For the past few days I have been loving recording audio on my iPhone 4 using an Azden SGM-2X (old but works like new). Today I went to record some more audio for a project and the red circle with the line threw it is in the "IN" box. When I try to record it says "recording unavailable". Even when I unplug the mic I get the same error message.
Any ideas?
Thank you!

[pwnified]

That's kind of weird. Please try rebooting the iPhone and try again, it might just be a one off bug with the iOS.

[artsie-girl]

I turned the phone off and then synced it with iTunes. I still have the problem.
I can record using Dragon Dictation no problem, with and without the mic.
Can I delete MultiTrack DAW from my iPhone and re-install it?

[artsie-girl]

How completely bizarre! The second re-boot worked!
Thank you! I will remember that if it happens again.
I LOVE this program, by the way . . . you're helping me get an "A" in my Audio Production class!

Thanks for everything!

[dzthings]

Same exact thing happened to my son using an iPod Touch 2nd gen with a homemade breakout cable. Everything worked fine for awhile, then all of a sudden he got the recording unavailable / crossed out input problem described above. Rebooting multiple times didn't fix anything. However, uninstalling and then reinstalling the app did bring it back. Hopefully this can be fixed - it would be a real shame to have to delete the app and loose work just to fix this.
BTW: Love the app otherwise...

[pwnified]

Actually in this case I would suspect the homemade breakout cable. These things can be very tricky to get working correctly, please see page 6 of the Input Options thread for a design that that uses a FET to isolate the bias voltage and provide a resistance low enough to get iOS to select it as an input source. The fact that reinstalling the app "fixed" the problem could have been coincidence, or it could just be that the cable is borderline of fulfilling the very specific requirements of the headset input port. On the iPods without an internal mic, you will get the red cross and the 'recording unavailable' if there is any issue at all with the headset mic. Another very common problem with the headset port is lint, that tends to collect inside the headset port and weaken the connection.

BTW, you won't loose any work when reinstalling MultiTrack if you use the iTunes backup and restore from backup, all song data is part of the backup process.

[dzthings]

I really appreciate the quick and clear response! Thank you for an excellent explanation.