Troubleshooting

File Loading Issues

Impulse CSV fails to load

Problem: You see an error toast when trying to load a CSV file.

Possible causes:

  • The matching *_Metadata.log file is missing from the same directory
  • The metadata file doesn’t contain Experiment date: and Experiment time: fields
  • The CSV uses a delimiter other than comma (Nexus requires comma-separated values)
  • The CSV is missing required Timestamp or Experiment time column headers

Solution: Ensure the metadata log file is in the same folder as the CSV and contains the required fields.

File format not recognized

Problem: Nexus doesn’t recognize the file you’re trying to load.

Solution: Check that the file extension matches one of the supported formats. Nexus primarily identifies file types by extension, with some content-based auto-detection for specific formats (for example, different CSV-based formats).

Authentication Issues

Can’t sign in

Problem: Clicking “Sign In” opens the browser but nothing happens in Nexus.

Possible causes:

  • The browser authentication completed but the local callback server could not receive the response.
  • A firewall or security tool is blocking connections on port 8888.

Solution:

  1. Ensure no other application is using port 8888.
  2. Temporarily disable VPN or firewall rules that block localhost connections.
  3. Close Nexus completely and try again.

Session expired

Problem: Nexus asks you to sign in again even though you recently authenticated.

Solution: If you have been offline for more than 7 days, re-authentication is required. Connect to the internet and sign in. See Offline Mode for details.

Performance

Application feels slow with large datasets

Possible causes:

  • Very large image series (thousands of frames) may use significant memory.
  • Many panels open simultaneously increase rendering workload.

Solutions:

  • Close panels you are not actively using.
  • Remove signals you no longer need from the workspace - this frees both frontend and backend memory.
  • If memory usage is high, restart Nexus to release all caches.

Nexus automatically manages memory with a 1 GB frontend frame cache and LRU eviction. Frames that haven’t been viewed recently are freed first.

Still having issues?

If none of the above solutions resolve your problem, please report a bug through our support portal. Include your Nexus version, steps to reproduce, and any error messages you see.