[BUG] lost most session data in the past 24h

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I have been claude code (CC) for months now. Today around 3pm ET I started claude code and tried reusming from where I left off yesterday, and noticed that only 1 session was left; I had about 100 sessions in the past 3 months.

I'm guessing it is the latest update that did something. I'm going to turn off auto-updated and setup a backup mechanism but this hurts.

What Should Happen?

sessions logs should not be deleted without user consent. If some backwards incompatible changes are required, the update should refuse to happen, or at very least should save the session data somewhere.

Error Messages/Logs

No errors, just the data is gone.

Steps to Reproduce

Unknown, but I have auto update on and everything was working fine yesterday till 5pm ET; today 3pm ET gone.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

unknown

Claude Code Version

I believe it is 2.1.5, can't check immediately as I am cloning the drive so I can attempt to recover the files

Platform

Google Vertex AI

Operating System

Ubuntu/Debian Linux

Terminal/Shell

iTerm2

Additional Information

_No response_