[BUG] Session data lost after app update — "디스크에서 세션을 찾을 수 없음"

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?

Bug Description

After a Claude Code desktop app update, a previously existing session's data was deleted from disk. The session still appears in the sidebar session list, but clicking it shows "디스크에서 세션을 찾을 수 없음" (Cannot find session on disk) with only "보관(Archive)" and "삭제(Delete)" options.

The disk has over 90% free space, so this is not a storage cleanup issue.

Steps to Reproduce

1. Have an existing session with conversation history
2. App update occurs (current version: v1.11847.5)
3. Open the previous session from the sidebar
4. Session data is gone — "디스크에서 세션을 찾을 수 없음"

Expected Behavior

Session data should be preserved across app updates. If migration is needed, data should be migrated — not deleted.

Actual Behavior

Session transcript files are completely removed from the ~/.claude/sessions/ directory after the update. The session metadata (title, ID) remains in the sidebar, but the actual conversation data is unrecoverable.

Environment

• App version: v1.11847.5
• OS: Windows 11 Pro 10.0.26200
• Lost session: "New bpgc" (ID: local_847ffce3-1df2-4d9f-86bd-3fd8139f273d, last activity: 2026-04-09)

What Should Happen?

Session data should be preserved across app updates. If data migration is needed, it should be migrated automatically — not deleted.

Error Messages/Logs

Steps to Reproduce

1. Have an existing session with conversation history (e.g., "New bpgc" session)
2. App updates to a new version (v1.11847.5)
3. Open the previous session from the sidebar
4. Session shows "디스크에서 세션을 찾을 수 없음" (Cannot find session on disk)
5. Session files are missing from ~/.claude/sessions/ directory

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v1.11847.5

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_