My first guess was that Software Update was set to auto-install, but in that case, why not Yosemite?

Quote:
The other thing that was all weird was the keychain access, asking for a password whenever you moved something.

Do you mean that you were asked for an admin p/w to move things?

Maybe a permissions thing; what were you trying to move?

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire