Symantec Version : Symantec AntiVirus 10 Corporate Edition
Operating System : Windows XP Professional
Culture : Australian (Just so the our US brothers and sisters are not confused by any dates in screenshots 🙂 )

Note: Windows XP is now out of support by Microsoft as of April 2014. This is not to say this process will not work on other operating systems or for other Symantec versions, just that this is the only system I have used this process on.

1. Download *.xdb

Download the virus definition file from the Symantec FTP site:
ftp://ftp.symantec.com/AVDEFS/norton_antivirus/xdb/

2. Get Current Version

Check the currently applied pattern file version and date by double click the Symantec shield icon in the system tray.

Open C:\Program Files\Common Files\Symantec Shared\VirusDefs\definfo.dat

Example content:

[DefDates]
CurDefs=20140101.001

You can see the relationship between the GUI display version and the CurDefs value from definfo.dat

3. Stop Symantec services

To allow us to change some of the file system is it a good idea to stop the Symantec services. This will prevent file locking whilst being in use. I strongly advise that you disconnect from the internet prior to stopping these services. For you and your computers protection.

net stop "Symantec AntiVirus"
net stop "Symantec AntiVirus Definition Watcher"
net stop "Symantec Event Manager"
net stop "Symantec Settings Manager"

Note: “Symantec SPBBCSvc” will not stop however this does not appear to be a problem. So it is safe to ignore it.

4. Is there enough free space?

Here are some files \ directories that can be deleted which can free up hundreds of MB of space each. I try to ensure there is at least 1GB free on my C: drive.

Delete the directories that do match the current applied definition file date \ version information from:
C:\Program Files\Common Files\Symantec Shared\VirusDefs
\tmp*.tmp\
\.xxx\

Delete the *.vdb that do not match to the currently applied pattern version from:
C:\Documents and Settings\All Users\Application Data\Symantec\Symantec AntiVirus Corporate Edition\7.5\

Delete the *.vdb directories that do not relate to the currently applied pattern version from:
C:\Documents and Settings\All Users\Application Data\Symantec\Symantec AntiVirus Corporate Edition\7.5\I2_LDVP.VDB\

5. Copy Virus Definition Files

Rename the downloaded .xdb to .zip
Extract the .vdb
Rename .zip back to .xdb
Rename the .vdb to .zip
Create a directory named “temp” in: C:\Program Files\Common Files\Symantec Shared\VirusDefs\
Extract all the files from the .zip to C:\Program Files\Common Files\Symantec Shared\VirusDefs\temp\

6. Manual update

Now for the majority of the manual steps.
Open C:\Program Files\Common Files\Symantec Shared\VirusDefs\temp\catalog.dat with Notepad

At the bottom of this file is a section like so:

[verInfo]
Date=20140528.003
HubDef=0

Copy the value of Date

Close catalog.dat

Rename the ..\temp\ directory to the value of Date copied from the [verinfo] section

Example:
Rename: C:\Program Files\Common Files\Symantec Shared\VirusDefs\temp\
To: C:\Program Files\Common Files\Symantec Shared\VirusDefs\20140528.003\

Navigate to the directory: C:\Program Files\Common Files\Symantec Shared\VirusDefs\
Make backup copies of definfo.dat and usage.dat
Edit usage.dat with Notepad
Update the version number in the square brackets [] to be the value of Date (captured above from ..\temp\catalog.dat)

Example From:

[20140101.001]
DEFWATCH_10=1
NAVCORP_70=1
NAVCORP_70_2=1

Example To:

[20140528.003]
DEFWATCH_10=1
NAVCORP_70=1
NAVCORP_70_2=1

Edit definfo.dat with Notepad
Move the value from CurDefs to be the value for LastDefs
Change the value of CurDefs to be the value of Date (captured above from ..\temp\catalog.dat)

Example From:

[DefDates]
CurDefs=20140101.001
LastDefs=20130925.003

Example To:

[DefDates]
CurDefs=20140528.003
LastDefs=20140101.001

7. Restart Symantec services

net start "Symantec Settings Manager"
net start "Symantec AntiVirus"
net start "Symantec AntiVirus Definition Watcher"
net start "Symantec Event Manager"

Start “Symantec Settings Manger” first as it is a dependency for the other Symantec services

Wait five (5) to ten (10) minutes after starting the services for the update to take effect. It usually takes less than five minutes.
Check if the pattern file has updated by double clicking the Symantec Antivirus system tray application

In this example the version has been updated to 28/05/2014 rev 3

There you have it.

References:
http://www.symantec.com/business/support/index?page=content&id=TECH101198
http://www.symantec.com/business/support/index?page=content&id=TECH95484
http://www.symantec.com/connect/forums/can-tmp-and-vdb-files-be-deleted
http://securityresponse.symantec.com/avcenter/defs.download.html
ftp://ftp.symantec.com/AVDEFS/norton_antivirus/xdb/