Not sure exactly what you're saying.
First, what version of AC and on what OS/platform are you running into this problem?
When you say CStone10 - I assume you really mean "CStone 10.jpg" (the library has a space before the '10')...
And, ArchiCAD does not support external textures - other than those loaded with Library Manager individually or via a parent folder or container. So, when you say 'external', I have to wonder if you your other textures are embedded ((meaning you are running a version of AC newer than 12)?
Maybe you can post screenshots of what Library Manager says is loaded, and of Attribute Manager set to the Materials tab and showing the problematic material?
Thanks,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB