I have this problem I don't know if it affects my computer in any way.
When I turn it on, I get the message:
PKCS # 7 signature not signed with a trusted key
Which appears in white or orange. I am concerned that it is something bad for my computer. I would like to know what it is and how to fix. I've investigated and would say that it is for the graphics card but I still don't know. The message began to appear when I restarted my computer. That message appeared before restarting it and now that I restarted it (after a while that message appeared, I still don't know why).
I have a Linux 2.9.0 Ubuntu 16.04, Intel Device Graphics Card 5a85