If your computer has a firewall, make sure that the firewall doesn’t prevent the relevant update applications from running.
Checking the firewall
Check your firewall and make sure that the following applications are allowed to access the Internet:
Sony Ericsson Update Engine.exe (If you are using a PC)
PCCompanion.exe (If you are using a PC)
Sony Ericsson Update Engine.app (If you are using a Mac computer)
Sony Bridge for Mac.app (If you are using a Mac computer)