I removed my battery today to view the support numbers on the back of my X5. After putting back the damn thing and turning on my X5 I got the question to:

1. Clear all data
2. Not clear my data and continue

I had to choose with the hardware buttons. When I choose the second option, it switched to a screen with the DELL logo and then it HALTED.. nothing worked. Tried it several times by removing the battery again, but it halted everytime...

So I had to choose the option to clear all my data and then the X5 continued as a new one... no data...

Does anyone ever had this problem? And how can I prevent this if I ever want to remove the battery again??

It has happened before. Three things to watch for:

1. The backup battery is snug in the pocket and making good contact.
2. The Axim is off when you remove the main battery.
3. The power button is NOT flashing.

On the backup battery, some folks have found the battery making poor contact. To fix that, remove the backup battery and clean it carfully with a tissue or soft cloth, then make sure the little fingers at the bottom of the pocket are high enough to make good contact. Some folks put a little padding on top of the battery to have the cover press it firmly into place.

Also, when removing the main battery you can have the Ax plugged into the power brick safely. I have done that every time I have had to remove my battery and I've never lost power.