The Patient Set Viewer and other ACT software requires a working directory. Here the software creates and updates files for background jobs, caching, and other tasks. The software needs create and write to this working directory.

1. Make sure you have an entry in ACT_config.php for working_directory
2. Create this path on your web server
3. Give write permission to the web server for this directory
   For example, on your DEV server  chmod 777 /opt/viewer_jobs

Make sure web (HTTP) access is not allowed to this directory

At least 0.5 Gigabyte of space is recommended for your working directory