Pen drive showing insert disk

Check your pend drive on some other system if the message is the same, it has become corrupt,replace it

The drive has been corrupt and needs to be formatted first before start using further. I'm afraid that you might lose all your data permanently if you haven't taken backup anywhere else.

Alternatively, you can follow the tutorial mentioned here and see if it helps you in fixing the corrupted or damaged hard drive (See reference link)

Good luck though!!

Data Recovery Tools