Last night I was working on some improved wall textures for my track. To date in building my track my walls have basically all been made with the default texture. I worked up a new texture for the walls and wanted to add same to all the walls on the track. I began with the first wall and began replacing the default texture with my new one. No issues at first. Oddly after replacing the first 15-20 seperate walls the program began to be non responsive to my highlight and replace texture request. When I then went back to the first 20 or so that had worked correctly either a) the texture had reverted to the original default texture or b) the new texture I had added in was only present on a half or a third of the wall- the rest had the old original default texture... Am thinking I might have to delete my walls and replace them all with new ones- a lot of work but it seems I would have no other choice if I want the better textures present. Has anyone else experienced this? Any ideas why this would happen? PS- I have been working on the track for over a year and this has never happened.