September 19 2017: This is now fixed. You'll need to uninstall the September 12 2017 update (KB4011086) then install Description of the security update for Outlook 2007: September 19, 2017.

After installing the September 12 2017 update for Outlook 2007 or Outlook 2010, some users were surprised to discover the language used for the menus and dialogs changed to another language. For example, the Italian language version now has menus in Portuguese and the Hungarian version has Swedish menus. The cause: someone built the distributions with incorrect language versions of OUTLLIBR.DLL in the language packages.

While Microsoft does not recommend removing the update, doing so will fix the problem. Alternately, users are reporting success with replacing just the OUTLLIBR.DLL file with an older version.

If you choose to uninstall the update (KB4011086 for Outlook 2007, KB4011089 for Outlook 2010), you’ll need to hide the update to prevent it from being reinstalled.

If you have an Outlook installation that has not yet been updated, you can copy OUTLLIBR.DLL to affected computers.

Copy OUTLLIBR.DLL

If you are using 64-bit Windows and 32-bit Outlook, OUTLLIBR.DLL is at C:\Program Files (x86)\Microsoft Office\Office12\[language id] in Outlook 2007 and C:\Program Files (x86)\Microsoft Office\Office14\[language id] if using Outlook 2010.

In 32-bit Windows, OUTLLIBR.DLL is at C:\Program Files\Microsoft Office\Office12\[language id] in Outlook 2007 and C:\Program Files\Microsoft Office\Office14\[language id] if using Outlook 2010.

The language id is a 4-digit number representing the language of your Office version.

Administrators can use the following script to replace OUTLLIBR.DLL on workstations with an older copy on a network share. Don't forget to change the language ID in the Office file path (and the network path).

You must have an copy of a 'good' OUTLLIBR.DLL for Outlook 2007 or Outlook 2010 to use this method.

@echo off

REM Is already deployed? (delete txt-file manually if fix needed)
if exist "\\Network\outlook fix\%computername%.txt" goto END

@echo off
taskkill /IM "outlook.exe" /f

:XCOPY
XCOPY "\\Network\outlook fix\OUTLLIBR.DLL" "C:\Program Files (x86)\Microsoft Office\Office12\1234\" /E /Y /C /Q

@echo off
REM Create a 'have deployed' check-file
echo %date% %time% %computername% > "\\Network\outlook fix\%computername%.txt"
goto END

:END
exit

How to uninstall updates

The steps are the same for Outlook 2010.

1. Open Control Panel, Windows Update
2. Click Change Settings
   
3. Change your setting to Download but let me choose whether to install them. Click OK to save the change.
   
4. Open Control Panel, Programs and Features and click View installed updates.
   
5. Search for the Outlook update installed this week and uninstall it. You can right click on it or select and click Uninstall at the top of the list.
   
6. Restart the Computer when it's finished uninstalling. (May not be required but is generally a good idea.)
7. Open Control Panel, Windows Update.
8. Check for updates. When it's finished, click on the found updates link.
9. Right-click on the Outlook update and choose Hide update. This will prevent it from being reinstalled. You can unhide it at anytime in Restore hidden updates.
   
10. After the update is hidden, you can turn auto updates back on.