The final version of Windows Desktop Search, (3.0 RTW) has been released by Microsoft. If you’re using Office 2007 B2TR, (including OneNote 2007) you most likely want to steer clear of this for now. According to the OneNote Extensibility & More blog:
Q: Does this work with OneNote/Outlook 2007 B2TR?
A: Probably not well! WDS changed and fixed a lot of issues between B2TR and now so this will fix a lot of search on the desktop but it will not work well with B2TR. Once the RTM version of Office 2007 is available it will work as expected.
Q: Should I upgrade now?
A: If you depend on search in Outlook/OneNote no matter how buggy it is in B2TR then keep working with the same version of WDS. Then when you have the final version of Office 2007 then you can install this final version of WDS 3.0. Otherwise if you depend on search on the desktop and you have issues with the current version upgrade to the final version, search in the Office apps may or may not work great.