Yes , it gives me the SD card access error message.
Your SD card has been corrupted..... There is a very simple fix for that error.
Connect the scanner to your computer in the Mass Storage mode with the SD card installed. Be sure you have installed a fresh set of batteries.
When connected to your computer, from the top menu in Sentinel, click "Home Patrol", then "clear user data", then check the box that says "display all drives". If the SD card is showing up there, select it and finish the "clear user data" process and then "write" to the scanner from Sentinel to restore your data, disconnect the scanner from the computer and let it re-boot.
If the SD card doesn't show up in the step above, or if you still get the error message, try reformatting the card using Windows with a card reader connected to your computer.... best to format using this program if errors continue:
and then go back to the "clear user data" step above. If the SD card still doesn't show up, or if you still get the error message, replace the card with a new one, and then start again at the the "clear user data" step above.