no sim problem

Another data point. Happens to me too. I either have to power cycle the phone, turn on Airplane mode and wait a bit, or a combo.

I think I'll take this in for replacement once the first few days simmer down. :-/

Yes, same problem here. I've had my phone for about 12 hours, and experienced this issue about 10 times. I have ejected the SIM, cleaned the contacts, but the only thing that brings the phone back most of the time is to reboot it. Then it will work for awhile, I'll wake it from sleep, and it will be displaying NO SIM. Doesn't seem like a SIM connection issue or due to vibration as the phone is just sitting on my desk. I made an appt. with a genius tomorrow. I hope they take my word for it as it is intermittent.
-Tony

I am having the same problem. No Sim Card message displaying after 30 minutes as an iphone 4 owner. I hope this doesnt mean a long wait for replacement. Has anyone found a solution?

I've had this problem as well. I rebooted, but the only thing that eliminated the error was to remove the SIM and reinsert it.

I spoke with apple support. They had me remove and reinsert. So far it is okay. I am just afraid that it will get the same message again.

I activated my iPhone 4 yesterday and it has been working fine. This evening I picked it up and it showed "no SIM" and I can't figure out what to do. I have removed the SIM and reinstalled it, rebooted (holding power and Home at the same time). I really don't want to have to go to AT&T tomorrow if at all possible. Does anyone have an idea of what to do? Thanks

I have the same problem - new iPhone 4.0 will work fine and then "No SIM Card installed" message appears and I lose Internet and phone capabilities. Only way to solve is to power down and restart. Works for a while and then....

My iPhone 4 showed up reporting "No SIM". I reseated it and it worked for a while, but then it failed again. After a SIM swap at the at&t store didn't fix it, I was able to get a new phone at a store this evening.

If you're having this problem, it looks like the equipment is going to have to be replaced.

Having the exact same issue. Had the phone for 28hrs perfectly fine, then last night about 8pm got the No SIM Installed message out of the blue. Tried re-seating with no success. Since this is my only phone, I tried calling AT&T customer service with my roommate's iPhone 4, had my call dropped 3 times and then on the fourth call, the rep told me that due to high volume I'd have to call back. By this time it was 11:30 at night and I couldn't keep my roomie up for a whole nuther hour so I made the earliest Genius appt I could at 12:30 this (Friday) afternoon. Our Apple store is right across from the AT&T store at the mall so hopefully I'll get a satisfactory response from at least somebody. Very frustrating and very disappointing. I hope I can get this SIM issue resolved so I can get back to making dropped calls and holding it wrong.

Im having the same problem in the UK, works for a while then it'll come up and say no sim installed, restarting or turning airplane mode on/off works but not for long, extremely frustrating. If anyone manages to fix this or find out what is wrong please let us know. Cheers

Same problem here. "No Sim" GRRRR!!! It's probably stupid AT&T!

I am having the same issues with a 32gb iPhone 4 on 02 upgraded and activated yesterday it started happening last night so I just reseated the sim in the holder and it came back. Happened three times again this morning & a restart sorted it for a while but now I just get the no sim message all the time even if I restart or reseat the sim. As i'm at work I cant get to my computer to reset until tonight so very frustrating.

I have spoken to O2 and they claim my sim is ok & I have put it into a nokia using the Micro Sim adaptor supplied and I am getting full signal and no issues

Same issues with mine. I have to pop the SIM out and then back in and it works fine after that. Did it 4 times yesterday an already 2 this morning with minimal usage. Now I have to carry around a paper clip in my wallet.

I tried it again this morning and for some reason, the phone is now working. This is almost more troubling than it just not working anymore. We'll see if it works through the day. This is unreal. Has anyone taken their phone to AT&T with this issue? I am curious if I should take mine in regardless of it working (for the time being that is). Have they replaced anyone's SIM cards or do they just reboot it and send you on your way?
This is very frustrating.
Thanks

OK, I removed the card and put it back in. So far no more problems, but I did notice a pretty good scratch on the card :-/