my_backup — WSL Archive Duplicate Filename Error & Fix

What Happened

WSL 7-Zip archive creation failed on May 1 and May 2 with:

ERROR: Duplicate filename on disk:
ta\.claude\projects\-home-ta-projects-monorepo-sites-Template
ta\.claude\projects\-home-ta-projects-monorepo-sites-template

Root Cause

Two pairs of case-variant orphaned Claude Code project directories in /home/ta/.claude/projects/:

-home-ta-projects-monorepo-sites-Template (capital T, Feb–Mar sessions) — source path /home/ta/projects/monorepo/sites/Template no longer exists; directory was renamed to lowercase template
-mnt-d-FSS-KB-mbr (lowercase, Apr 6 sessions) — source path /mnt/d/FSS/KB/mbr doesn’t exist; real path is uppercase MBR

Claude Code creates .claude/projects/ entries when you open a project. When a directory is renamed (case change), the old entry is never cleaned up. On Linux both coexist (case-sensitive). Windows 7-Zip treats them as duplicates.

Fix

Deleted both stale directories:

/home/ta/.claude/projects/-home-ta-projects-monorepo-sites-Template
/home/ta/.claude/projects/-mnt-d-FSS-KB-mbr

Audit command for future reference: ls ~/.claude/projects/ | tr '[:upper:]' '[:lower:]' | sort | uniq -d

Verification

Ran full backup from Windows (uv run my_backup --with-7zip --skip-hooks):

✓ WSL: Created with warnings (1.20 GB) — archive created successfully
Exit code 0, 1 warning (pre-existing FSS “file in use” warning, unrelated)

Notes

Not related to the May 2 mystery-folders fix (different failure mode)
LESSONS.md updated in my_backup repo