Kryterion Webassessor & Sentinel: Common Errors and How to Fix Them

Kryterion delivers online-proctored certification exams through Webassessor (the registration and scheduling portal) and Sentinel Secure (the lockdown client). Sentinel adds a biometric layer: you enroll a typing pattern and a face image, and those are re-verified at launch. That extra layer is where most Kryterion-specific problems appear.

Sentinel Secure will not install

Sentinel requires administrator rights and a supported operating system. Install it well before exam day.

Fixes: run the installer as administrator on Windows; on macOS approve it in Privacy & Security and grant Camera, Microphone and Screen Recording, then reboot; uninstall older Sentinel versions first; and never attempt an install on a work-managed laptop with software restriction policies — use a personal machine.

Biometric enrollment fails or will not match at launch

Enrollment captures a typing rhythm for a short phrase and a face photo.

• Type at your natural pace during enrollment. If you enrolled while typing carefully and then type normally at launch, the pattern will not match.
• Enroll on the same keyboard you will test on. A laptop keyboard and an external mechanical keyboard produce very different rhythms.
• Re-enroll from your Webassessor profile if matching keeps failing — this is a self-service action and takes two minutes.
• For the face capture, use even frontal lighting, remove hats and glasses if prompted, and keep a plain background.

Launch errors and "exam not available"

Confirm you are inside your scheduled window — Kryterion exams open at the appointment time, not before, and the portal shows a launch button only during the window. Check the time zone on your registration. If the button is present but nothing happens, Sentinel is not installed or an older version is installed; reinstall the current client from Webassessor.

Camera, audio and bandwidth

The usual rules apply and they are strict here: no second monitor, no other applications, a wired connection where possible, and camera permissions granted at the operating-system level. Sentinel closes prohibited processes at launch; if it cannot, it refuses to start, so reboot and open nothing else.

During the exam

A remote proctor watches the feed. Keep your face visible, do not read aloud, keep the desk clear, and do not use a phone or leave your seat. If the connection drops, wait for the client to recover before taking any action, then relaunch from Webassessor and contact support with your registration ID if the session does not restore.

The universal pre-exam checklist

Roughly nine out of ten proctoring incidents trace back to the same five conditions. Run this list the day before, not fifteen minutes before.

• Use the same machine, browser and network you will test on. A system check passed on a laptop at home does not certify the desktop at work.
• Reboot fully. A cold restart releases the camera handle that Zoom, Teams, Discord, OBS, Snap Camera or Windows Camera quietly kept open.
• Update the browser and the secure application. Version mismatch is the single most common launch failure.
• Test upload, not download. Live proctoring streams video *out*. You need a stable 1.5–3 Mbps upload; a 500 Mbps download does not help if upload collapses.
• Disable VPNs, proxies, corporate firewalls, parental filters and antivirus web shields. Managed work or school devices block the ports proctoring platforms use, and administrators cannot always unblock them in time.

Fast diagnostic sequence when something breaks

1. Note the exact error code or message and screenshot it — support resolves coded errors in minutes and vague descriptions in hours.

2. Check whether the failure is *device*, *network* or *account*. Device: the check fails offline too. Network: it fails only on this connection. Account: it fails on every device.

3. Switch one variable at a time: hotspot instead of Wi-Fi, Chrome instead of Edge, second machine, guest OS profile.

4. Re-run the vendor system check and save the report ID.

5. Contact live support *before* the appointment window closes — most vendors will not reinstate a session once you have exceeded the launch grace period.

What to do if the session is lost anyway

If the exam terminates, do three things immediately, in this order: screenshot the error, open the vendor's live chat and get an incident or case number, and email your institution or licensing board the same day with that number attached. Reinstatement decisions almost always hinge on documented, timestamped evidence created during or immediately after the incident — not on a request filed a week later.

Then use the retake window deliberately. Rehearse the launch flow on the exact machine, run one full-length timed practice test under the same conditions, and treat the technical setup as part of your study plan rather than an afterthought.