Z zefaty New member Joined Jun 5, 2014 Posts 4 Jun 5, 2014 #1 While installing service pack 1 getting error : "Error: TRUST_E_NOSIGNATURE(0x800b0100)". Tried "Readyness tool" with no result , troubleshooting the same. I have to apply SP1 without reinstalling Windows . Just tell me please what do you need for solving the problem. Thank you.