How much memory do you have options > status File Free.
This number should be more than 12,xxx,xxxmb or this will keep
happenning to you. If it is less than 12mb take your battery out
without turning off the phone, leave it out for 30 secs, put it back
and check your memory again.
You lost them cause of low memory! Go to Options>Status, and check File Free status. You should have a minimum of 12,000,000 free bytes in order for your BB to function smoothly. If you're low on memory, follow the instructions on this thread to help you out.
After you finish with the memory optimization, make sure all your media items (I.e. pics, music, video etc.) are stored on a media card. When you lose memory, your BB will start to delete the least important items to free up memory. This includes texts, emails and call logs. Try to keep an amount above or around 12,000,000 free bytes.
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