Hello,

Welcome to the Dell Community Forum.

Sometimes this may have caused if the Upper and lower filters in the registry are corrupted, you can fix it by deleting the upper and lower filters from system registry and restarting the system. 

Steps to locate the upper and lower filters depends upon which operating system you are using. 

If you need help in locating the upper and lower filters, reply with the operating system you are using. I will be glad to help. 

-Niranjan