nicolas@tp-w530:~$ sudo LANG=C apt-get update
Ign http://archive.canonical.com trusty InRelease
Ign http://de.archive.ubuntu.com trusty InRelease                              
Ign http://security.ubuntu.com trusty-security InRelease                       
Ign http://extras.ubuntu.com trusty InRelease                                  
Hit http://archive.canonical.com trusty Release.gpg                            
Ign http://ppa.launchpad.net trusty InRelease                                  
Ign http://dl.google.com stable InRelease                                      
Ign http://download.jitsi.org unstable/ InRelease                              
Hit http://security.ubuntu.com trusty-security Release.gpg                     
Ign http://de.archive.ubuntu.com trusty-updates InRelease                      
Hit http://archive.canonical.com trusty Release                                
Hit http://extras.ubuntu.com trusty Release.gpg                                
Ign http://ppa.launchpad.net trusty InRelease                                  
Ign http://dl.google.com stable InRelease                                      
Hit http://security.ubuntu.com trusty-security Release                         
Ign http://de.archive.ubuntu.com trusty-backports InRelease                    
Hit http://download.jitsi.org unstable/ Release.gpg                            
Ign http://ppa.launchpad.net trusty InRelease                                  
Hit http://extras.ubuntu.com trusty Release                                    
Hit http://archive.canonical.com trusty/partner amd64 Packages                 
Hit http://de.archive.ubuntu.com trusty Release.gpg                            
Hit http://security.ubuntu.com trusty-security/main Sources                    
Ign http://dl.google.com stable InRelease                                      
Ign http://ppa.launchpad.net trusty InRelease                                  
Hit http://download.jitsi.org unstable/ Release                                
Hit http://archive.canonical.com trusty/partner i386 Packages                  
Hit http://extras.ubuntu.com trusty/main Sources                               
Hit http://security.ubuntu.com trusty-security/restricted Sources              
Hit http://de.archive.ubuntu.com trusty-updates Release.gpg                    
Hit http://dl.google.com stable Release.gpg                                    
Ign http://ppa.launchpad.net trusty InRelease                                  
Hit http://extras.ubuntu.com trusty/main amd64 Packages                        
Hit http://security.ubuntu.com trusty-security/universe Sources                
Hit http://download.jitsi.org unstable/ Packages                               
Hit http://dl.google.com stable Release.gpg                                    
Get:1 http://de.archive.ubuntu.com trusty-backports Release.gpg [933 B]        
Ign http://ppa.launchpad.net trusty InRelease                                  
Hit http://extras.ubuntu.com trusty/main i386 Packages                         
Hit http://security.ubuntu.com trusty-security/multiverse Sources              
Hit http://dl.google.com stable Release.gpg                                    
Hit http://de.archive.ubuntu.com trusty Release                                
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://security.ubuntu.com trusty-security/main amd64 Packages             
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://dl.google.com stable Release                                        
Hit http://de.archive.ubuntu.com trusty-updates Release                        
Hit http://security.ubuntu.com trusty-security/restricted amd64 Packages       
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://dl.google.com stable Release                                        
Hit http://de.archive.ubuntu.com trusty-backports Release                      
Err http://de.archive.ubuntu.com trusty-backports Release                      
  
Hit http://security.ubuntu.com trusty-security/universe amd64 Packages         
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://dl.google.com stable Release                                        
Hit http://de.archive.ubuntu.com trusty/main Sources                           
Hit http://security.ubuntu.com trusty-security/multiverse amd64 Packages       
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://dl.google.com stable/main amd64 Packages                            
Hit http://de.archive.ubuntu.com trusty/restricted Sources                     
Hit http://security.ubuntu.com trusty-security/main i386 Packages              
Hit http://ppa.launchpad.net trusty Release.gpg                                
Hit http://de.archive.ubuntu.com trusty/universe Sources                       
Hit http://dl.google.com stable/main i386 Packages                             
Hit http://security.ubuntu.com trusty-security/restricted i386 Packages        
Hit http://ppa.launchpad.net trusty Release                                    
Hit http://de.archive.ubuntu.com trusty/multiverse Sources                     
Hit http://security.ubuntu.com trusty-security/universe i386 Packages          
Hit http://ppa.launchpad.net trusty Release                                    
Ign http://archive.canonical.com trusty/partner Translation-en                 
Hit http://de.archive.ubuntu.com trusty/main amd64 Packages                    
Hit http://security.ubuntu.com trusty-security/multiverse i386 Packages        
Ign http://extras.ubuntu.com trusty/main Translation-en                        
Hit http://ppa.launchpad.net trusty Release                                    
Ign http://archive.canonical.com trusty/partner Translation-de                 
Hit http://de.archive.ubuntu.com trusty/restricted amd64 Packages              
Hit http://security.ubuntu.com trusty-security/main Translation-en             
Ign http://extras.ubuntu.com trusty/main Translation-de                        
Hit http://ppa.launchpad.net trusty Release                                    
Hit http://dl.google.com stable/main amd64 Packages                            
Hit http://security.ubuntu.com trusty-security/multiverse Translation-en       
Hit http://ppa.launchpad.net trusty Release                                    
Hit http://de.archive.ubuntu.com trusty/universe amd64 Packages                
Hit http://dl.google.com stable/main i386 Packages                             
Hit http://security.ubuntu.com trusty-security/restricted Translation-en       
Hit http://ppa.launchpad.net trusty Release                                    
Hit http://de.archive.ubuntu.com trusty/multiverse amd64 Packages              
Ign http://download.jitsi.org unstable/ Translation-en                         
Hit http://ppa.launchpad.net trusty/main amd64 Packages                        
Hit http://de.archive.ubuntu.com trusty/main i386 Packages                     
Ign http://download.jitsi.org unstable/ Translation-de                         
Hit http://de.archive.ubuntu.com trusty/restricted i386 Packages               
Hit http://dl.google.com stable/main amd64 Packages                            
Hit http://security.ubuntu.com trusty-security/universe Translation-en
Hit http://dl.google.com stable/main i386 Packages                   
Hit http://ppa.launchpad.net trusty/main i386 Packages               
Hit http://de.archive.ubuntu.com trusty/universe i386 Packages
Hit http://de.archive.ubuntu.com trusty/multiverse i386 Packages
Hit http://ppa.launchpad.net trusty/main Sources
Hit http://de.archive.ubuntu.com trusty/main Translation-en
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit http://de.archive.ubuntu.com trusty/main Translation-de
Hit http://ppa.launchpad.net trusty/main i386 Packages
Hit http://de.archive.ubuntu.com trusty/multiverse Translation-en
Hit http://de.archive.ubuntu.com trusty/multiverse Translation-de
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit http://de.archive.ubuntu.com trusty/restricted Translation-en
Hit http://ppa.launchpad.net trusty/main i386 Packages
Hit http://de.archive.ubuntu.com trusty/restricted Translation-de
Hit http://de.archive.ubuntu.com trusty/universe Translation-en
Hit http://de.archive.ubuntu.com trusty/universe Translation-de
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit http://ppa.launchpad.net trusty/main i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/main Sources
Hit http://de.archive.ubuntu.com trusty-updates/restricted Sources
Hit http://de.archive.ubuntu.com trusty-updates/universe Sources
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit http://de.archive.ubuntu.com trusty-updates/multiverse Sources
Hit http://ppa.launchpad.net trusty/main i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/main amd64 Packages
Hit http://de.archive.ubuntu.com trusty-updates/restricted amd64 Packages
Hit http://de.archive.ubuntu.com trusty-updates/universe amd64 Packages
Hit http://de.archive.ubuntu.com trusty-updates/multiverse amd64 Packages
Hit http://ppa.launchpad.net trusty/main amd64 Packages              
Hit http://ppa.launchpad.net trusty/main i386 Packages               
Hit http://de.archive.ubuntu.com trusty-updates/main i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/restricted i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/universe i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/multiverse i386 Packages
Hit http://de.archive.ubuntu.com trusty-updates/main Translation-en
Ign http://dl.google.com stable/main Translation-en
Hit http://de.archive.ubuntu.com trusty-updates/multiverse Translation-en
Ign http://dl.google.com stable/main Translation-de
Hit http://de.archive.ubuntu.com trusty-updates/restricted Translation-en
Ign http://dl.google.com stable/main Translation-en
Hit http://de.archive.ubuntu.com trusty-updates/universe Translation-en
Ign http://dl.google.com stable/main Translation-de
Ign http://dl.google.com stable/main Translation-en
Ign http://dl.google.com stable/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Ign http://ppa.launchpad.net trusty/main Translation-en
Ign http://ppa.launchpad.net trusty/main Translation-de
Fetched 933 B in 3s (282 B/s)
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://de.archive.ubuntu.com trusty-backports Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>

W: Failed to fetch http://de.archive.ubuntu.com/ubuntu/dists/trusty-backports/Release  

W: Some index files failed to download. They have been ignored, or old ones used instead.