Today I fixed a problem that I had on my hard drive. When I re-installed elementary-os (from the latest iso), the App Center had 21 new updates. I clicked the Update All button and after some time I logged off. When I logged back in I couldn't see the Panel at the top. Note that I have not changed anything that could affect the system and it was (almost) a fresh installation of elementary-os.
Edit: There is one update in the app center that I cant install.
Op. Sys. updates, 245 components