The last twice I have taken the battery out and inserted a fresh charged one the settings have been lost and I have had to Re-enter the Time and date.

This hasn't happened before - is there a reason why this is happening and not keeping these setting?

I swap batteries almost every day and never had to re-enter anything.

i though that was only me! In the first changes of batteries the configs doesnt reset but now i have to enter manually time and date when i change batts and that doesnt happen at beginning :S

Quick question did you happen to purchase the spare batteries from Ebay?

This happens to me too. About half the times I swap the battery I have to re-enter the settings. I haven't yet been able to work out why.

Both batteries are official nokia, bought from the nokia shop. Battery charger is from eBay

I also have to re enter the date as well and the annoying thing is the auto update of time doesnt work neither

same here, happens 50% of the time, my battery is genuine from nokia.co.uk

Me too, phone bought from london Nokia flagship store in december so no chance of any of my components being fake

well the time and date are usually maintained when the battery is removed by a small watch type battery in the phone. i've found they run out after a year or so on most of my other phones, but i have no idea why it would burn so quick on your n900's, but if thats the culprit you may be able to have a nokia service centre change it. hope this helps.

Well the problem is if you all taken the battery out more than 10-20seconds without replacement within that 10seconds then the electrical charge built up inside the conductor in the N900 will be depleted and which lead to storage setting lost during that time.

Due to N900 designed flaws, there is no emergency battery for the bios to keep the date and time setting intact like other devices. eg: symbian.

The N900 cannot keep the date and time setting for more than 10seconds (sometimes can be 20seconds) after the battery is taken out or depleted completely. That is why when the battery is low to 4% threshold, the device will shut it self down and going in a coma to save it's setting from being lost.

If you changing battery, you will have to do it very quickly within the 10seconds time frame, otherwise N900 will result in amnesia symtom.

I hope my explaination is clear and helpful. I hope the software is smart enough to preserve the setting and syncronise it with the provider in the future.