This error can occur for a number of reasons but is related to an external storage device like external hard drive or USB drive. It can occur when attempting to access contents on a external device or copying content to a device (i.e. transferring videos or screenshots).
You can try the following things to try and fix the issue:
- If the storage device is connected but you see this error, disconnect it and reconnect it. This can be done by pressing the PS button to access the quick menu and selecting [Sound/Devices] > [Stop Using Extended Storage], and then disconnecting the physical device.
- Make sure the storage device is FAT or exFAT formatted. Any other format (e.g. NTFS) will not work.
- Connect the storage device to another device, e.g. a laptop or PC and confirm that it works.