I copied all information from my memory card on to spare memory card , now spare memory card is working fine , original memory card works but computer will not recognise original card, although it still works on TomTom . TomTom home also does not see original memory card so will not update mapshare information.
Unit is TomTom 520 running 8.396 with latest truck 870.3421 and UK 870.3406.
Thanks for fast replies biggerdave and yuriyggg, I have tried your advice biggerdave and still same and was going to try yuriyggs advice but noticed that original sd card is coming seperated from itself near sd lock switch , so I think that this is the problem . I tried card in my old tomtom one v1 and although TomTom one works with this card computer will not see it as a drive. So I believe the proplem is the card itself is damaged .
Will update to newer navcore when new card arrives .
Many thanks for your fast advice , this is a fantastic site !