If you are experiencing problems with V-Ray, it’s possible to review the error log located in the ProgramData / Application Data folder of your computer.
This can be found:
On Windows XP:
C:\Documents and Settings\All Users\Application Data\ASGVIS\VfS\vfs_stderr.txt
On Windows Vista and Windows 7:
C:\ProgramData\ASGVIS\VfS\vfs_stderr.txt
On Mac OS X:
/Applications/ASGVIS/VfS/vfs_stderr.txt
The error log is cleared each time you open SketchUp, and it won’t be fully written to unless SketchUp is completely closed. Therefore, as soon as an issue manifests, close SketchUp and open the error log file in order to view any reported issues.
Any problems with mismatched materials or similar should result in an entry in the error log. Most common issues include incorrect bitmap paths, corrupt materials, textures, or components. Unicode characters within file paths can also cause errors.