vBulletin Manual - Planning the import

This section should be read fully before an import to understand the process and what steps should be taken to ensure a smooth transition. This is vital to performing a smooth import and minimizing the disruption to your community.

The three most important things to do now are:

Note:

LEAVE THE ORIGINAL BOARD RUNNING UNTIL YOU HAVE READ THIS AND DONE SOME TEST IMPORTS.
Back up your target database.
Read the rest of this manual for importing.
Testing an import before shutting down the source forum is the best way to go.
There will probably be some residual HTML from the content that will need cleaning up afterwards, which is part of the import task and process, not a function of the support team.
The links within the forum to other threads/posts/users will be imported, and link to the old board. A 301/404 solution will need to be put in place if that is a concern.