This is a new thing …. freezing in the middle of dropping videos, etc., and building preview is really slow.
In addition to Nat's queries, what is the resolution of the source files - HD, 2K, 4K?
Prior to editing, have you allowed VP to cache completely? Usually this is confirmed by solid green lines above each track's thumbnails and, at times, a light purple line that paints itself under the preview window.
