To comment your message :
The file RDG-F1507004.jpg is not crypted and normally before when I click with the left button, the file was open in XN view which is the default program of this extension, like png too. So your remark about the association of jpg with not axx extension is not my fact, it is automatic with the right button !!! and I don’t know why ?
In other hand, If I click on the right button on try with the same files and choose open with xnview, it is open correctly without any message from Axcrypt
So even if the files does not have any axx extension, the Axcrypt message is displayed (I try to rename as you said in RDG-F1507004-jpg.axx unfortunately with the same message. This kind of dysfunction was appears just after install version 2