Windows: Marketplace update permanently wedged by stale .bak directory (EPERM rename loop)

Environment

• Windows 10, Claude Code 2.1.101 (native), Git Bash shell

Problem

On Windows, claude plugin marketplace update gets permanently stuck after a single failed update. Every subsequent update attempt (including automatic startup syncs) fails silently, leaving all installed plugins in "failed to load" state.

Root cause

The marketplace update algorithm does a rename dance:

1. Fetch fresh content to <name>.staging/
2. Move current <name>/ → <name>.bak/
3. Move <name>.staging/ → <name>/

If any step fails, rollback tries: rename <name>.bak/ → <name>/

On Windows, fs.rename() returns EPERM when the destination directory already exists (unlike POSIX). Once a .bak/ directory is left behind from a failed attempt, every future update fails because:

• Step 2 can't rename live → .bak (destination exists)
• Rollback can't rename .bak → live (live still exists since step 2 failed)
• .staging/ gets re-fetched every session but never promoted

Symptoms

• /doctor reports all installed plugins as "not found in marketplace"
• claude plugin list shows all plugins as "✘ failed to load"
• Error: EPERM: operation not permitted, rename '...claude-plugins-official.bak' -> '...claude-plugins-official'

Fix applied manually

Deleted stale .bak/ directory, then claude plugin marketplace update succeeded immediately (log even said "Found stale directory, cleaning up and re-cloning").

Suggested fix

Before the rename dance, delete any pre-existing .bak/ directory (or use a unique temp name). The .bak/ is just a rollback buffer — stale ones from prior runs have no value and should be cleaned up.