Some iPhone 4S users report SIM card issues

maybe they should stop dropping their phone.

Interestingly, I had this problem with my iPhone 4. I traced it to a case with a magnetic latch. When the phone was in the case, it wouldn't recognize the SIM card. When I replaced the case, it stopped happening.

Before more of you with absolutely no experience of this issue chime in with rubbish - this is a hardware issue and not a SIM card or carrier issue.

My brother had this issue. He used a micro sim from an iPhone 4 which worked perfectly with his iPhone 4. He got SIM failure problems with his brand new iPhone 4S from day 1.

First replacement SIM card from Orange UK - looked identical - small, new contacts on the micro sim - worked ok for 2 days then sim card not recognised again.

Spoke to Apple - was told to do a clean restore and try a new sim card (again).

iPhone restored and 'setup as new phone' - new sim card inserted - worked ok for a few hours then sim card not recognised again.

Finally went to the Apple store for a genius appointment after jumping through all the hoops - swapped the iPhone for a new one - same sim card that was getting sim failure and sim card not recognised - 1 week and not 1 problem.

I think this proves it is a hardware issue and not a SIM card / carrier issue.

Each sim failure / sim card not recognised fault could be fixed by a reboot only. Nothing in the software could fix it (toggling data settings, airplane mode etc.)

ALSO - the iPhone 4 saw the introduction of the micro sim to the iPhone - the iPhone 4 sim card issue can be attributed to poor sim cards IMO - i had the problem with the iPhone 4 which i bought on launch day, my replacement sim card had made the contacts smaller and i didn't have a problem after that. I think all the carriers rushing to mass produce micro sims caused quality issues.

I had that problem with iPhone 4... and the problem disappears selecting manually the operator instead of automatic. Give it a try!

My wife had this problem. Both she and I have cropped normal sim card, but hers one is old model (with bigger chip), mine SIM was normal size, but with smaller chip. Before both of the SIMs worked on all the iphones (Original, 3g, 3gs, 4), but now mine works with both 4s, but hers fails. Perhaps this is due to support both GSM/CDMA, perhaps contact pad touches wrong chip tracks..

i had same issue on my iPhone 4 (bought unlocked from canada) but only after i've upgraded to iOS5. i started to have problems catching signal anytime i went out of the underground. re-booting and re-installing the phone helped only temporarily. i've got my iPhone changed and with the brand new unlocked unit i wasn't able to use any of my previous micro sims that used to work without issues on iOS 4 (t-mobile for the US, sunrise for switzerland, t-mobile for czech republic). i had my US t-mobile micro sim changed and only that one is working now. the chip looks different from the previous micro sim. is it maybe iOS related?

I have had this problem intermittently with my wife's AT&T iPhone 4 for the past several weeks. AT&T replaced the SIM but the problem still occurred. I also tried replacing the little SIM carrier. No joy; intermittent "No SIM card installed messages. Rebooting fixed temporarily.

I replaced the iPhone 4 with a new AT&T 64GB 4S today. I also have a 4S myself since first day. No problems so far. I suspect this is an AT&T issue, or maybe bad contacts.

Hope there is an easy answer.

Had the SIM failure on my Verizon iphone4S after upgrading to iOS 5.0.1. I went to the local VZW store and they simply opened he SIM door and sprayed compressed air in there. No problems since.

I had a friend with this problem on Verizon. I popped out the SIM card, reseated it, and it hasn't given an error out since. It seems the tray/SIM seating is very sensitive?

My iPhone 4S stopped recognizing it's SIM a day after I got it. A new SIM didn't fix the issue and Apple swapped the phone out with a replacement.