Respondus LockDown Browser Error Codes on Mac (Complete 2026 Reference)
Error code summary table
| Code / message | Meaning | Mac-specific cause (most common) | Dedicated fix page |
|---|---|---|---|
| -7 | Network or proxy failure | macOS firewall or Little Snitch blocking Respondus endpoints | Error -7 fix |
| -21 | Configuration mismatch | LDB cached config corrupted from prior partial download | Error -21 fix |
| -101 | General config (server side) | Course's Respondus Dashboard not configured | Error -101 fix |
| -105 | General config (server side) | Same - Dashboard issue | Error -105 fix |
| -106 | General config (server side) | Same - Dashboard issue | Error -106 fix |
| -111 | General client/server config | LDB version mismatch with Dashboard | Error -111 fix |
| -118 | General config / network | Same - usually caching | Error -118 fix |
| A4 | Update check failed | Network blocked Respondus update endpoint | Error A4 fix |
| Installation Failed | Installer package failure | Corrupted .dmg from interrupted download | Installation Failed fix |
| 1000+ codes | Server-side | Course or institution Dashboard misconfiguration | Contact university IT |
Source: Respondus Error Codes KB; verified on macOS Sonoma 14.6 and Sequoia 15.4 with LDB 2.1.5.x across the LDBypass test fleet.
Why most numbered errors trace to Mac caching
The "0 to 199" range error codes that Respondus groups together share a root cause more often than the documentation suggests: a stale LDB cached state. LockDown Browser writes a small per-course configuration to ~/Library/Application Support/LockDown Browser/ on first launch, including a copy of the Dashboard config it pulled from your university's Respondus server. When this cache disagrees with what the server returns at the next launch - common after a course is re-published, after a Dashboard update on the institution side, or after LDB itself is updated - the client surfaces a -21, -101, -105, -106, -111, or -118 error rather than re-syncing automatically.
The reliable fix on Mac is to delete the entire Application Support directory, then relaunch LDB from your LMS:
rm -rf ~/Library/Application\ Support/LockDown\ Browser/
rm -rf ~/Library/Caches/com.respondus.lockdownbrowser/This procedure preserves your /Applications/LockDown Browser.app bundle (no reinstall needed) but discards every cached course configuration. The next launch downloads the current Dashboard config fresh, which fixes the mismatch causing the error.
When the error is your university's, not yours
Error codes in the four-digit range (1000+) and some -101 / -105 / -106 cases when they appear despite a successful cache-clear and reinstall almost always indicate the misconfiguration is in your university's Respondus Dashboard. From the Mac client side these errors are unfixable. Telltale signs the issue is server-side:
- Classmates on identical Mac configurations and identical LDB versions cannot launch the same exam either.
- The error appeared right after your professor edited the assessment.
- The error is the same on a freshly-installed LDB on a different Mac.
- The error references "course not configured", "instructor must approve", or similar institutional language.
In these cases contact your instructor or your university's IT desk. Respondus's own support channel will redirect you to your institution because Respondus support cannot edit your specific course's Dashboard config.
Articles in this section
- LockDown Browser Error -7 on Mac (Network Error Fix 2026)
- LockDown Browser Error -21 on Mac (Configuration Mismatch Fix)
- LockDown Browser Error -101 on Mac - Server-Side Configuration Fix
- LockDown Browser Error -105 on Mac (Server Configuration Fix)
- LockDown Browser Error -106 on Mac - Configuration Issue Fix
- LockDown Browser Error -111 on Mac (Version Mismatch Fix)
- LockDown Browser Error -118 on Mac (Configuration / Network Fix)
- LockDown Browser Error A4 on Mac (Update Check Failed Fix)
- LockDown Browser "Installation Failed" on Mac - Complete Fix Guide