If you update TRAKTOR to version 2.5.0 for the first time, the software will re-analyze your music tracks due to its improved Analysis functionality.
You can re-analyze your whole collection at once by right-clicking on the Track Collection node in TRAKTOR's Browse Tree and choosing Analyze (Async) from the context menu. The Analyze box will appear, offering several new options.
Important Note: If you uncheck the box Set Beatgrid, you will completely delete the beatgrid and will not be able to use features such as syncing or automatic looping.
Be aware that the beatgrids will be reset unless you have locked the BPM in the GRID panel. This applies to your manually beatgridded tracks as well, so make sure they are locked prior to performing the new Analysis. The lock icon needs to be lit up in orange if you want to keep a grid. Additionally, a lock icon will appear next to the song in the Browser.