Hi Lumaja,
Textures are just images that sit on your computer and TFP links to them. You get a message if for example you put grass on a floor because grass is in the Landscape group so does not logically belong on a floor, but it is still just an image and the program does not know what is on the image, only the group you took it from. If fact, via the Catalogue Manager, you can change what material groups give you a warning, so if you wanted you could tell it to accept Landscape materials on the floor or roof (or bricks on the wainscot) if you wanted and you would not get a warning. Probably the only danger with using your own images as textures is using ones that are too big in file size.
I checked previous posts on corrupting the catalogue and none I found related to materials. One I experienced many years ago was certainly unrelated but did highlight the need to do a backup from time to time. Having said that I have never had to revert to a backup because of a corruption of the catalogue.
Most corruptions are of the model itself (not the catalogue), and usually caused by bad joins in walls. It is probably good practice to use the File/ Repair Project occasionally so you find any model corruptions belfore you go too far. The corrupt elements will be deleted.
If you are planing to do VERY close-up renders that will include the brick texture I provided you may want to provide another close-up photo of the bricks so it can be done at a better resolution. If you are not planing very close renders then if will probably be fine.
Allan
