Cannot slide to answer phone calls

Hello,

I have the exact same problem.
It happens about 1 call over 4, so it is very often and extremely annoying. I'm thinking of getting a full refund because of this. It literally makes the phone unusable. This is a much more important problem then the antenna problem.

The exact problem (on iPhone 4 (MC603FB) with iOS 4.0.1 (8A306)):
The phone has to be in lock mode (screen turned off). Then I get a call and the slide to answer arrow appears (it can be someone from my contacts or not) and the green arrow simply doesn't move at all ! Not a single pixel, just like if the screen was dead. Then when the phone stops ringing, the message missed call appears with the slide to unlock below. And here again, the slide to unlock just won't move at all ! But I just press the power button twice (screen goes off then back on) and the slide to unlock works perfectly without a single glitch. I have tried several times, the slide to unlock doesn't move at all and I press the power button twice and it slides without problem (this is systematic). The slide to unlock hangs ONLY after having a call that I cannot answer. If I press the power button or home button while the phone is lock, then the slide to unlock always works, I never had the problem in other cases.

@msedaka: I don't have any of the apps you have. But I have a lot of others (59). I also have photos but only 247 (5 songs and 4 videos).

For info: I am in France using Bouygues Telecom.

In my opinion this is absolutely not a hardware problem (neither dirty finger problem): because if a press the power button twice immediately after having the problem, the problem goes completely away, also I have never dropped the phone. It does not have something to do with contact info or option having to load or anything because I have this with people from my contact or not. It does not have something to do with the signal strength either: I had the problem even with full signal strength. Pressing the home button doesn't help. Also I cannot refuse the call by pressing the power button while having this problem, but right after the call is missed I can press the power button to turn off the screen.

If someone from Apple reads this: please ask me for any other details and / or ask me to do some tests that I will do the next time I have the problem. I am really willing to help because this is a major problem of the iPhone that seems to exist since a long time (I'm saying this from what I see on forums, not my own experience (I only have an iPhone 4, and only since one month)). I am myself a developer so I know what can and cannot be the source of the bug. I will continue to make tests over this problem and report them here.
It would be good if the other peoples having this problem reports more details (does the power button works to refuse call? does the green arrow move a bit or not at all? what signal strength did you have at this moment? can you slide to unlock once the call is missed? if not, does it help to press the power button twice? does it happens with people only from your contacts or everyone?)


Thank you for your consideration of this major problem.

Have someone call you from a number not on your phone, bet it works fine. Check your contact info and you probably have a ringtone that is no longer on your phone assigned to the person. I assigned a standard ringtone on the contact and now it works fine.

Phone seems to have a delay issue with a contact having a ringtone not on phone.

I have exactly the same problem. Very frustrating, dealing and answering the calls is a main function of the phone. I would feel a lot better if I knew this is a software proplem that will be fixed soon and not hardware. Otherwise will need to buy another phone.

A lot of people have this problem -
http://forums.macrumors.com/archive/index.php/t-750100.html.

If you have drop your phone you are going to have this problem. Now it a hardware problem. You have to replace your phone. No fix for that. Part need to be change.

No! I have not ever dropped it - I've noticed this problem second day after buying it.

Then you should have replaced it. It's a hardware problem.

If you have the same problem with multiple phones you need to try this:
Have someone else try your slider on in incoming phone call and see if the have the same results. Your screen senses your touch and reacts. Might sound stupid but maybe your skin temperature is outside the limits at time. Can't think of another reason why you could have this periodically on different phones that you have tried.