EthoVision Experiment File Opens with 'Inconsistency' Warning or Fails to Load – Incomplete Experiment Folder
Last updated: Nov 01, 2026
Problem
When opening an EthoVision experiment file (.evxt), the software displays an inconsistency or error message, or the file fails to load correctly. This can occur after moving, copying, or extracting the experiment from a ZIP archive.
Details
EthoVision experiment files require the full experiment folder structure (including associated subfolders and supporting files) to be intact and co-located with the .evxt file. If only the .evxt file is present (e.g., because empty folders were omitted when zipping/extracting), or if the folder was moved without all its contents, EthoVision will report an inconsistency. A 'lock error' (.vtl file present) may also appear if EthoVision previously crashed; this is a separate but commonly co-occurring symptom. Disk space issues can also cause incomplete experiment files. See also: 'EthoVision .vtl Lock File Found in Experiment Folder' and 'EthoVision Experiment File Fails to Open – Database or File Error'.
Solution
1. Ensure the complete experiment folder is present. The .evxt file must remain in its original experiment folder alongside all associated subfolders (e.g., video files, data files, arena files). Do not move or open the .evxt file in isolation.
2. If the experiment was extracted from a ZIP archive, check that all subfolders (including any that may have been empty) were included in the ZIP and extracted correctly. Re-zip and re-extract if needed, ensuring all folders are included.
3. Check available disk space on the drive where the experiment is stored. A full drive can cause experiment files to be written incompletely. Free up space if necessary.
4. If a .vtl lock file is present in the experiment folder, this indicates EthoVision previously crashed while the experiment was open. Delete the .vtl file and attempt to open the experiment again.
5. Try opening the automatic file backup: in EthoVision, go to File > Open Backup, or look for backup files in the experiment folder (typically named with a date/time suffix).
6. If the experiment still fails to open, contact Noldus support and upload the full experiment folder (including all subfolders) via ShareFile or WeTransfer for diagnosis.