A dataset is defined as using a file but the file specified cannot be found.

How to fix

Ensure that the supplied file exists in the same directory as the file defining the dataset.

Problem example:

{
  "datasets": [
    {
      "name": "CustomCities",
      "type": "File",
      "file": "cities.txt"           // File doesn't exist
    }
  ]
}

Ensure that the supplied file exists in the same directory as the file defining the dataset:

File structure:

my-project/
├── masking.json                   // Your masking file
├── cities.txt                     // Dataset file (same directory)
└── options.json                   // Your options file

Valid dataset configuration:

{
  "datasets": [
    {
      "name": "CustomCities",
      "type": "File",
      "file": "cities.txt"           // File exists in same directory
    }
  ]
}

cities.txt example:

Seattle
Portland
Vancouver
Spokane