The problem is surely antivirus. Comodo firewall runs in background even if you disable the firewall and that causes problem with SDK.I too had the same problem.1.run comodo settings2.defense+3.list active processes4.add adb.exe to trusted processes5.restart server: run 'adb kill-server' 'adb start-server'For Comodo 6.x1.Open Comodo2.Click Tasks Icon at right top3.Click Advanced Tasks4.Click Open Advanced Settings5.Select Security Settings - File Rating - Trusted files from left panel6.Click on the upward arrow icon at the bottom7.Click Add - add the adb.exe.