Solution.
1. You must to find "modified.log" in
C:\Users\*YOURUSER*\AppData\Roaming\The Creative Assembly\Shogun2\logs
and open that file. It lists the files that are modified.
2. You need to delete them from
C:\Program Files (x86)\Steam\steamapps\common\Shogun2\data.
Usually these files are
local_en_patch.pack unknown file
patch.pack unknown file
patch10.pack unknown file
patch11.pack unknown file
patch12.pack unknown file
patch13.pack unknown file
patch14.pack unknown file
patch15.pack unknown file
patch16.pack unknown file
patch17.pack unknown file
patch18.pack unknown file
patch19.pack unknown file
patch2.pack unknown file
patch20.pack unknown file
patch21.pack unknown file
patch22.pack unknown file
patch23.pack unknown file
patch3.pack unknown file
patch4.pack unknown file
patch5.pack unknown file
patch6.pack unknown file
patch7.pack unknown file
patch8.pack unknown file
patch9.pack unknown file
patch_bp.pack unknown file
patch_fots.pack unknown file
patch_fots2.pack unknown file
patch_fots3.pack unknown file
patch_fots4.pack unknown file
patch_fots5.pack unknown file
patch_movies.pack unknown file
patch_movies2.pack unknown file
patch_movies3.pack unknown file
patch_movies4.pack unknown file
patch_movies5.pack unknown file
patch_movies_fots.pack unknown file
patch_movies_fots2.pack unknown file
shaders_patch.pack unknown file
shaders_patch10.pack unknown file
shaders_patch11.pack unknown file
shaders_patch12.pack unknown file
shaders_patch13.pack unknown file
shaders_patch14.pack unknown file
shaders_patch2.pack unknown file
shaders_patch3.pack unknown file
shaders_patch4.pack unknown file
shaders_patch5.pack unknown file
shaders_patch6.pack unknown file
shaders_patch7.pack unknown file
shaders_patch8.pack unknown file
shaders_patch9.pack unknown file