OBS crashing on startup or when you go live: how to find the cause

What it looks like in your log

Unhandled exception: c0000005

Why does OBS keep crashing on startup, and how do I fix it?

A crash on launch is usually a third-party plugin that does not match your OBS version (common right after an OBS update), a broken source in the active scene collection, or a GPU driver problem. A crash when you press Start Streaming or Record usually points at the encoder, for example a hardware encoder that fails when streaming and recording use separate encoders at once. On Windows, the crash report (not the regular log) starts with a line like "Unhandled exception: c0000005", and the module names listed under it show which DLL was running when OBS died. Since OBS 30, OBS offers Safe Mode after it did not shut down properly; Safe Mode starts without third-party plugins, scripts and WebSockets, so if OBS opens there, a plugin or script is the likely cause.

How to fix it

1. Before changing anything, back up your setup: copy the obs-studio folder (on Windows %APPDATA%\obs-studio, on macOS ~/Library/Application Support/obs-studio). Scene collections are in basic/scenes and profiles in basic/profiles.
2. Relaunch OBS and accept the Safe Mode prompt, or start it with the --safe-mode flag.
3. If it opens in Safe Mode, remove or update third-party plugins one at a time until normal launch works.
4. If it still crashes in Safe Mode, update your GPU driver and test with a new, empty scene collection to rule out a broken source.
5. If it crashes only when you go live or record, set streaming and recording to share the same encoder (Recording: Same as stream) or switch one of them to x264, then test again.
6. Read the newest file in the obs-studio crashes folder, or use Help → Crash Reports → Upload Last Crash Report once OBS opens, to see which module failed.
7. After a clean session, upload your OBS log to StreamRx at streamrx.io to check for dropped, skipped or missed frames.