LockDown Browser on Mac - The Complete Technical Guide (2026)

Last updated 2026-05-01 · LDBypass Editorial

Quick directory

What is Respondus LockDown Browser

Respondus LockDown Browser is a custom-restricted web browser used by universities to deliver online exams through learning management systems (LMS) such as Canvas, Blackboard, D2L Brightspace, Moodle, Schoology, and Sakai. The browser disables tab switching, copy-paste, screenshot capture, screen-sharing, and most printing while an assessment is open. When paired with the optional Respondus Monitor service, the same client also records the test-taker's webcam, microphone, and screen for instructor review afterwards.

On macOS the application is delivered as a notarised, Developer-ID-signed bundle that the student installs via a university-provided link. The Mac client has been a Universal Binary (native arm64 + x86_64) since version 2.0; older 1.x builds required Rosetta 2 on Apple Silicon. The current production build at the time of this guide is LockDown Browser for Mac 2.1.5.01 (released March 2026), available from the official Respondus download page via the link your institution provides.

LockDown Browser is published by Respondus, Inc. (Redmond, WA, U.S.), founded 2000. It is not a Web browser engine of its own - recent Mac builds embed Apple's WebKit through WKWebView for page rendering, which is why behaviour can shift after a Safari/WebKit update even when the LDB version stays constant.

Compatibility matrix (LDB version × macOS × chip)

Source: Respondus release notes for 2.1.5.01 and 2.1.5.00; verified on the LDBypass test fleet (M2 Air / M3 Pro / M4 Max). For Apple Silicon-specific behaviour see the compatibility cluster.

Installation on macOS - overview

Installation always starts from your university's LMS, never from the public Respondus website directly. The download URL is institution-specific because LDB binds to your university's Respondus Dashboard configuration; an LDB build downloaded from another institution will refuse to launch the exam. Once you click the download link from your course, your browser receives a notarised .dmg (~50-90 MB depending on build) that mounts to /Volumes/Install LockDown Browser and contains a single installer package.

The installer requires admin authentication on macOS Sonoma and later. If your Mac account is a "Standard" user (no admin rights), you cannot install LDB without your administrator's password - Respondus does not ship a per-user install path on macOS. Apple Silicon Macs running LDB 2.0+ no longer require Rosetta 2; only LDB 1.x requires it. After install, the application lives at /Applications/LockDown Browser.app.

For LMS-specific install paths (Canvas, Blackboard, D2L Brightspace, Moodle), Rosetta 2 troubleshooting, and admin-password workarounds, see the installation cluster.

When LockDown Browser won't open - overview

"Won't open" is the highest-volume search query for LDB on Mac and almost always traces to one of four causes: a Transparency, Consent & Control (TCC) permissions reset that left LDB asking for Screen Recording or Camera access via a hidden dialog; a corrupted LDB cached install state from a prior partial download; one of the Mac processes Respondus has blacklisted (AppleVNCServer, ARDAgent, screen-sharing daemons, certain Citrix and Parallels helpers) running in the background; or an LDB build mismatch between what your professor's Respondus Dashboard expects and what is installed on your Mac.

The fastest first attempt is to force-quit LDB (⌘ + ⌥ + Esc), reset Screen Recording permission via System Settings → Privacy & Security → Screen & System Audio Recording, and relaunch. This single fix resolves roughly 60% of the "won't open" reports we have reproduced on Sonoma 14.6 and Sequoia 15.3 across the LDBypass test fleet.

For the full diagnostic ladder - stuck loading, freeze on launch, crashes, quit-unexpectedly, black screen, force-quit procedure, keeps-closing, and unresponsive-during-exam - see the won't-open cluster, which links to a dedicated entity page for each symptom.

Numbered error codes - overview

Respondus has documented a finite set of numbered error codes that LDB surfaces on Mac: -7 (network or proxy failure), -21 (configuration mismatch), -101, -105, -106, -111, and -118 (general "0 to 199" range, mostly LMS-server-side configuration), A4 (update check failed), plus the textual errors "Installation Failed", "Digital Signature Error", and "Configuration Failed".

Most numbered codes resolve from the macOS side by clearing LDB's cached configuration (~/Library/Application Support/LockDown Browser/) and reinstalling from your university's current LMS link. Codes that begin "-1018" or appear in the 1000+ range almost always indicate a Respondus Dashboard misconfiguration in your specific course, not a Mac client problem - your university IT or instructor needs to check the dashboard side.

For a complete code-by-code reference with Mac-specific causes and fixes, see the error codes cluster. The canonical Respondus reference is their error-code KB article.

Camera, microphone, and screen permissions - overview

Apple's TCC subsystem mediates every camera, microphone, screen-recording, and accessibility request on macOS Big Sur 11.0 and later. LockDown Browser requires three TCC permissions at the absolute minimum: Camera and Microphone when Respondus Monitor is enabled, and Screen & System Audio Recording for the kiosk-mode screen capture that detects unauthorised content. Some institutions also request Accessibility permission to enforce additional restrictions and Full Disk Access on rare configurations.

The "spinning wheel during webcam check" symptom that dominates Reddit threads almost always traces to a Camera permission that was granted then revoked by a macOS minor update. macOS Sequoia 15.3+ added a 30-day re-confirmation prompt for Screen Recording permissions that has caused fresh TCC dialogs even on installations that worked the previous semester - Respondus's official guidance covers the reset procedure.

For each permission's reset path, the difference between Sonoma's and Sequoia's settings panes, and the rare Accessibility/Full-Disk-Access scenarios, see the permissions cluster.

macOS + Apple Silicon compatibility - overview

LDB's Mac compatibility matrix changes twice per academic year on average: once with the September macOS release, and once with the spring LDB release that catches up. The compatibility cluster maintains a per-version status page for each currently-supported macOS major version (Ventura 13, Sonoma 14, Sequoia 15, and Tahoe 26 as it ships), plus per-chip pages for M1, M2, M3, and M4 (and their Pro/Max/Ultra variants) and for the legacy Intel reference. Each page tracks confirmed-working LDB builds, known issues, vendor-acknowledged bugs, and our reproduction notes.

The annual pattern: a new macOS developer beta in June introduces TCC or WebKit changes that break LDB; Respondus issues an advisory acknowledging the issue within a month; a fixed LDB build typically ships 4-8 weeks after the macOS public release in September. Universities that move students onto the new macOS before LDB catches up (often forced by Apple's deprecation of older macOS major versions for security updates) generate the largest support spike of the year.

For the per-version compatibility matrix and the Apple Silicon chip-by-chip pages, see the compatibility cluster.

Privacy and data collection - overview

What Respondus LockDown Browser sees and what Respondus Monitor records are different questions. LDB alone reads only the active exam window's contents, the list of currently-running processes (to detect blacklisted apps), and basic system identifiers (hostname, OS version, hardware UUID). It does not access your Documents folder, Safari history, or Time Machine backups. Respondus Monitor, when enabled by the instructor, additionally records the webcam stream, microphone audio, and a periodic screenshot of the active exam window for the duration of the assessment, uploading the recording to Respondus servers for instructor review afterwards.

The privacy debate around remote proctoring is substantive. The Electronic Frontier Foundation (EFF) has published multiple critiques of remote proctoring tools; several U.S. universities - Cleveland State, Yale Law, the University of Illinois at a few schools - have restricted or banned their use; class-action lawsuits in 2021-2024 have alleged Fourth Amendment violations in public-university deployments. Respondus's own privacy policy documents what is collected and the retention period (typically the duration of the academic term plus a configurable retention window).

For the public-source-only privacy analysis - what each tool says it collects, what independent researchers have observed, the lawsuit timeline, and the universities-that-banned-it list - see the privacy cluster.

Performance impact on Mac - overview

LockDown Browser is heavier than a regular browser tab but lighter than most Electron-based competitors. On a 2024 MacBook Air M2 with 16 GB RAM running macOS Sonoma 14.6, LDB 2.1.5.01 with Respondus Monitor active uses approximately 720-820 MB of resident memory and 15-25% sustained CPU on a single performance core during a 60-minute exam, with the largest CPU spikes during the initial webcam analysis pass and during page transitions. Battery drain on the same hardware measures roughly 9-12% per hour in our standardised 90-minute reproduction with the screen at 50% brightness - meaningfully higher than Safari (~4-6% per hour at the same workload) but lower than Chrome with the same exam open (~14-18% per hour due to Chrome's background services).

The most common performance complaints - high CPU, slow scrolling, battery drain, beachball events - almost always trace to one of three causes: an Intel-build LDB running through Rosetta on Apple Silicon (only relevant for legacy 1.x); Spotlight indexing the exam recording in real time on smaller-RAM Macs; or third-party security tools (Malwarebytes, Bitdefender, Sophos) scanning every screen-capture frame.

For our full benchmarks across M-series chips, the per-cause troubleshooting ladder, and the battery-drain methodology, see the performance cluster.

Uninstallation - overview

LockDown Browser stays installed after your exam ends. Respondus does not push an automatic uninstaller; the application remains in /Applications and its support files remain in ~/Library/Application Support/LockDown Browser/ and ~/Library/Caches/com.respondus.lockdownbrowser/ until you remove them manually.

A complete removal requires deleting the application bundle, the Application Support directory, the Caches directory, the LaunchAgents entry (if your university's deployment installed one), and the Group Containers directory used for Respondus Monitor recordings (which can occupy several gigabytes after a semester of exams). A minimal "drag the app to Trash" uninstall leaves several hundred megabytes of state on your Mac.

For the complete removal procedure, the leftover-files reference, and the clean-reinstall path used when a corrupted state is suspected, see the uninstall cluster.

Exam flow - overview

A typical LDB exam on Mac has a predictable shape: pre-launch system check (camera, microphone, photo of student ID, environment scan when Respondus Monitor is enabled); LMS authentication; password entry if your instructor set one; the exam itself in kiosk mode (no tab switching, no copy-paste, no screenshots, blocked Spotlight); a "submit" confirmation; and an exit dialog that sometimes - but not always - re-enables the rest of macOS.

Several behaviours surprise first-time users: LDB intentionally hides the macOS clock in the menu bar, so the exam timer in the LMS is the only visible countdown; Cmd-Tab is intercepted, so trying to alt-tab out of the exam triggers a violation log; and an unexpected Wi-Fi disconnection during the exam pauses LDB's connection to the LMS - answers entered while offline are usually preserved and submitted on reconnect, but the exact behaviour depends on the LMS.

For the full pre-exam checklist, the disconnected-internet recovery procedure, the "how to exit early" question, the timer behaviour, and the disabled-copy-paste workarounds, see the exam-flow cluster.

External monitors, webcams, and audio peripherals - overview

LDB on Mac actively detects external displays. By default the application refuses to launch the exam if a second monitor is connected - your instructor's Respondus Dashboard configuration determines whether this is enforced as an error or a warning. The detection is based on CGDisplayList (the same Core Graphics call System Information uses), so simply unplugging the HDMI/USB-C cable to your external display before launching LDB resolves the warning. Sidecar (using an iPad as a second display) is detected as an external monitor and triggers the same warning.

USB webcams and Bluetooth/USB microphones are supported - Respondus Monitor's webcam-check picks the system default. AirPods and most Bluetooth headsets work for the microphone but introduce a delay during the webcam-check audio-test phase that occasionally causes the check to fail; switching to the Mac's built-in microphone for the system check, then back to AirPods after the exam starts, is the documented workaround.

For the per-peripheral reference (dual monitors, USB cams, AirPods, Bluetooth headsets, Sidecar, USB-C docks), see the hardware cluster.

Software conflicts - overview

LockDown Browser maintains a "blacklisted application" list - running processes that prevent the exam from launching. The list is configured per-institution by the instructor through the Respondus Dashboard, but typically includes screen-sharing daemons (AppleVNCServer, ARDAgent, screensharingd), remote-control tools (TeamViewer, AnyDesk, Citrix Workspace, GoTo Resolve), VPN clients (some configurations flag any VPN), and certain accessibility tools.

Beyond the explicit blacklist, several Mac-side tools cause subtler conflicts: Grammarly's system-wide service intercepts text fields and trips a kiosk-mode check; Dropbox's Smart Sync occasionally locks files LDB's update-check writes; Malwarebytes and Bitdefender scan every screen-capture frame and double LDB's CPU usage; certain Little Snitch rules block Respondus's telemetry endpoints and cause silent failure to upload exam recordings.

For the per-conflict reference (Grammarly, Zoom, Dropbox, Malwarebytes, VPN, Citrix, Parallels), see the conflicts cluster.

When to contact your university IT

The LDBypass guides cover the Mac side comprehensively. Some failures, however, originate from your specific course's Respondus Dashboard configuration and cannot be diagnosed without your university IT or your instructor checking the server side. Escalate to your university IT desk if:

• Error codes in the 1000+ range appear (these are usually Dashboard-side).
• The exam works on classmates' Macs running the same macOS and LDB versions but not on yours, AND a clean LDB reinstall does not fix it.
• You receive an "Exam unavailable" or "Course not configured" error after LDB launches successfully.
• Your university account changed (password, MFA, SSO) between download and exam launch.

Most universities publish their own LDB-on-Mac help page; ours generally complements rather than replaces them. Search "[your university name] respondus lockdown browser mac" to find the local page; it contains contact information specific to your institution.