The location of the normal.dotm template is always the "User Templates Folder" set in Word advanced Options. If you set that location to be a thumb drive and it is not accessible, Word will create a new normal template elsewhere, which may mean a lot of confusion down the road. The normal template, in the course of regular use, is modified (edited) fairly frequently. Doing this while it is on a thumb drive may result in the loss of the file.

Better, IMO, would be to put your macros in a separate template, not in the normal template. Load that template as a Global Template by putting it in your Word Startup Folder. If that Startup Folder (set in Word advanced Options as well) is a thumb drive, do not edit any files directly on that drive. Do the editing on your hard drive and copy to/from the flash drive.