When LiveUpdate is used to Upgrade the Netbackup client version, you might be seeing issues that LiveUpdate is failing with the message:
"20.06.2013, 12:25:58 GMT -> HttpSendRequest (status 304): Request succeeded - File up to date so download is not required" in log.liveupdate or in the NetBackup job details you also can find the information "No Updates found".
This problematic you can only find when the Upgrade to the version 126.96.36.199 was done with LiveUpdate. LiveUpdate always downloads newer files than this what it has already in its local cache directory: f.e. "C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads"
When the LiveUpdate prepares to download f.e. symantec$20netbackup$20x86$20windows_7.1_english_livetri.zip the files is always checks for the time stamp and when this file is already present in the local cache with a newer modification date, than LiveUpdate wont download this file.
As Netbackup 7.5 was released erlier than the Netbackup 188.8.131.52 its LU files has as well the older time stamp.
Netbackup 184.108.40.206 LiveUpdate bundle:
19/03/2012 16:56 185,068,179 1332171690jtun_nb_220.127.116.11.winnt.x86.zip
19/03/2012 16:57 45,624,044 1332171690jtun_nb_jav_18.104.22.168.winnt.x86.zip
Netbackup 7.5 LiveUpdate bundle:
08/02/2012 19:27 225,661,095 1328614459jtun_nb_7.5.winnt.x64.zip
08/02/2012 19:27 166,592,635 1328614459jtun_nb_7.5.winnt.x86.zip
08/02/2012 19:29 2,978 nbclient$5fhp$2dux$2dia64_7.1_english_livetri.zip
As those files for Netbackup 7.5 are older, LiveUpdate will not download them and finish with the above messages.
Workaround 1: Remove / Delete the content in the folder C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads on each remote client where they are present.
Workaround 2: Delete / remove the LiveUpdate cache on remote clients (Control Panel > LiveUpdate -> Cache)
Workaround 3: Change the Modification date of the "Netbackup 7.5 LiveUpdate bundle files" to be newer than the files from Version 22.214.171.124
So the Workaround 3 is just one change in the LiveUpdate repository which will resolve those issues on all remote clients automatic when the criteria are matching the above scenario.
As well the pre requirements for the above steps is the Netbackup LiveUpdate Guide