Depending on a user's file access permissions, FileIn node thumbnail images may not display in Shake if writing a file to the cache directory is prohibited.
Symptom
Shake does not display the source material image thumbnails of FileIn nodes in the NodeView window.
Solution
Create a definition file for configuring your environment and specify a folder to which the disk cache should be written. You can create a definition file using a plain text editor such as TextEdit. Here's an example of how to create a definition file: