Symantec LiveUpdate stops downloading after 3500KB and sometimes hits 7000KB and stops with the below error. You use a proxy on your network. Symantec Backup Exec 2010 installed on Windows Server 2008.

Click below image to enlarge

Resolution

1) Access Control Panel
2) Access Symantec live Update
3) change LiveUpdate Configuration HTTP settings to “I want to customise my HTTP settings for LiveUpdate”
4) Enter proxy IP and port number
5) Change the Update Cache size to 30MB and click” ‘remove all files from cache’.
6) Close backup Exec and open again
7) Run LiveUpdate from Backup Exec again

Resolution 2
or

 1) In C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate, open and edit “Settings.LiveUpdate” using notepad

2) Locate the below lines towards the end of the file and amend the following parameters:
    PREFERENCES\INTERNET_CONNECT_TIMEOUT=45
    PREFERENCES\INTERNET_READ_DATA_TIMEOUT=45

3) Amend to 450 (see below):

    PREFERENCES\INTERNET_CONNECT_TIMEOUT=450
    PREFERENCES\INTERNET_READ_DATA_TIMEOUT=450

4) Save file