Depends on what storage and what files. If they are files created by the system, or files relating to an app, it is completely possible that you are restricted from opening them. This is quite common, on any kind of device.
Now if they are files you put there yourself, then you just need the right app to open them. One that opens that type of file.
If, however, they are none of the above, then it may be time to check the device for viruses, malware, etc.