Short answer: Force quit the Codex app, reopen it and click the blue update button in the top left if one appears (the app will close and relaunch on the new version), then start a new chat inside the same project. Do not fork the old conversation, a fresh chat is the reliable fix. This is a known compaction bug, not a broken setup and not anything you did wrong.
Here is the exact error people are pasting to me this morning:
It looks alarming. It is not. You did not break anything, and you do not need to reinstall, reconfigure, or start your setup over. Two minutes and three steps and you are back to work.
The Fix
- Force quit the app. Not just closing the window, fully quit it. On a Mac, right click the Codex icon in the dock and choose Quit, or use Force Quit. This clears the stuck session that is throwing the error.
- Reopen it and update. When it opens, look at the top left. If there is a blue button there, that is an update. Click it and let it install. The app will close again on its own and relaunch on the new version, that is expected, not a crash. The update clears the underlying bug, so take it whenever it is offered. If there is no update button, you are already current and step 3 is your fix.
- Start a new chat in the same project. Do not reopen the long session that threw the error, and do not fork it either. Forking copies that entire long conversation into the new thread, and that long conversation is the exact thing that broke compaction, so a fork tends to fail the same way. A brand new chat starts empty, so there is nothing to compact. Keep it inside the same project and it still has your files and business context, so you start fresh without losing your setup.
That sequence clears it for almost everyone. If you want to understand why it happened so you can avoid it next time, here is the plain-English version.
What the Error Actually Means
Two things happened, and neither is your fault.
First, "Context automatically compacted." Your conversation got long. To keep going without running out of room, Codex tried to compress the conversation automatically. That part is normal and expected. The clue that the session had grown large is the very end of the error, "column 600357," which points to a payload in the hundreds of thousands of characters.
Second, and this is the real culprit, "unknown variant auto, expected high or original." In plain terms: your app received a setting value it did not recognize. The newer version of Codex uses a value called auto, but the build you are running only knows high and original. When the older app got handed the newer word, it did not know what to do with it and stopped.
That is a version mismatch in the compaction system, and it is a known bug, not something unique to your machine. It has been reported on the Codex desktop app on macOS running Apple Silicon. Here is how the three steps map to it: force quitting clears the stuck process, the update clears the bug when a newer build is available, and the new chat is what actually gets you working again, because an empty conversation has nothing to compact.
If It Keeps Happening
If the error comes back after you update, check three things.
- Confirm the update actually installed. Reopen the app and look again for a blue update button. If it is gone, you are current. If it is still there, the update did not finish, so run it again.
- Do not nurse one giant chat all day. The longer a single conversation runs, the more often Codex has to compact it. Start a fresh chat for each new task. It is faster and it sidesteps the compaction step entirely.
- Make sure your context lives outside the chat. If you are worried about losing your place when you start fresh, that worry is the real signal: your business context should live in your files and your home base, not trapped inside one conversation. When it does, any new chat already knows your business. If that foundation is not built yet, start with the Codex setup guide for business owners.
The Pattern Behind Most Codex Errors
Keep this for the next time something looks broken. The majority of "my Codex stopped working" moments are not deep technical failures. They are one of three things: the app is out of date, a single session has gotten too big, or a connection lapsed. The first response that clears most of them is the same one above. Force quit, update, fresh start.
You are not behind because you hit an error. Every operator running real work on an agent hits these. The difference is knowing that the scary red text usually means start a fresh chat, or update the app, not redo your whole setup.
Quick Answers
What does "unknown variant auto, expected high or original" mean? It is a known Codex compaction bug. Your build got handed a setting value (auto) its parser does not accept, since it only takes high or original, so the auto-compaction fails and the thread stops. Start a new chat to keep working, and update the app to clear the underlying bug.
Why does it say "context automatically compacted"? Your chat got long, so Codex tried to compress it to keep going. Starting a new chat avoids it.
Should I fork the conversation instead of starting a new chat? No. Forking copies the long conversation that broke compaction into the new thread, so it usually hits the same error. Start a clean new chat in the same project instead.
How do I update Codex? Force quit, reopen, and click the blue update button in the top left. The app relaunches on the new version.
Will I lose my work? No. Old chats stay. And if your business context lives in your files and home base instead of one conversation, a new chat already has everything it needs.
Force quit, update, fresh chat. Then get back to the work.