On my current project we use ClickOnce, and I am setting up the build server to sign using a proper cert rather than a self generated one.
mage.exe -New Application -ToFile <path>\App.exe.manifest -name "<Name>" -Version 0.1.1.1 -FromDirectory <path>\0.1.1.1\ -IconFile App.ico -CertHash "ca5da5a1f7c57411111111a79cbf50c4432ed949"
And was getting
This certificate cannot be used for signing - "ca5da5a1f7c57411111111a79cbf50c4432ed949"
I was searching for what extended attributes are required, checking if I got the right thumbprint and wasted a bunch of time.
The fix was simple, remove the quotes around the thumbprint