Just as the title says, I get the 'no sim card installed' message occasionally and it says 'no sim' where the signal strength bar should be. This can be fixed with me turning the phone off and on again. It seems odd that this only started yapping after I got the official unlock through o2. It's not such a huge deal yet, as it's only happened 3 times in the past month, though I can see it turning into a real annoyance as I can't seem to pin it down to anything. I would just like to know if this has happened to anyone else, or even if it's a regular occurance for others.