Hi Mary,
Let us follow the methods listed below and check if it helps.
**Method 1:**Check if the files are hidden, follow the steps given below.
a) Open Windows explorer.
b) Click on View option at the top.
c) Now select options.
d) Select Change folder and search options
e) In the folder options Window, select view tab.
f) And select Show hidden files, folders and drives.
g) Click on Ok.
If the issue persists, run Hardware and device troubleshooter.
Method 2: Run the Hardware troubleshooter and check.
Follow the steps to run the troubleshooter:
a) Press Windows key + C on your keyboard to show the Charms bar.
b) Type Troubleshooting and click Troubleshooting under Settings.
c) Now type Hardware Troubleshooter in the search option.
d) Click on Hardware troubleshooter to run the troubleshooter.
If the issue still persists, try connecting the SD card to a different computer and check.
You can also contact Lexar support regarding this.
Hope the information was helpful, if you have any further queries, feel free to post. We will be glad to assist you.