antivirus shows virus in pen drive, even if there is no virus actually

i'm using Avast antivirus. it is working properly and updating itself regularly. but it has a problem(or may be not) that it shows virus whenever i insert pen drive in my PC.Every time i delete this virus or Move it to the chest of antivirus(later i delete it from the chest), it again appears. When i remove the pendrive it disappears.
many times i've inserted no virus pendrive but it shows "same virus" in those pendrives also.
now what should i do to completely remove the virus(it is not trojen). please suggest me . thanks.

Could you please let me know about the name of the Virus so that i can find the proper and exact solution for you. So requesting you to provide the name of the Trojan virus which is detected every time when you insert the Pen Drive. This is not the fault of the Avast. There might be the virus which is automatically generating every time when you insert the Pen drive.

This should be cause of hidden data of that pen. Format will solve this problem

It could be a different kind of spam or actually a "smart Virus"
OR
Your avira is infected! :rofl_2: :thumbup1:

Avast hehee oops