Desktop: Files written to /home/claude/ instead of project working directory

Description

Claude Desktop writes output files to inconsistent and incorrect locations:

1. Wrong root entirely: Wrote to /home/claude/CC_INSTRUCTION_VALIDATE_CONFLUENCE_CORE16.md instead of the project working directory (C:\Users\Cassie\Desktop\trading_system)
2. Inconsistent subdirectories: Previously wrote reports to docs/, then started writing to reports/, with no user-requested change

Environment

• Platform: Claude Desktop (latest version, Windows)
• OS: Windows 10/11
• Project root: C:\Users\Cassie\Desktop\trading_system
• Date observed: January 29, 2026

Expected Behavior

Files should be written relative to the project working directory consistently, respecting the directory structure the user has established.

Actual Behavior

• Desktop uses /home/claude/ as the write path (appears to be a Linux sandbox/container path leaking through)
• Output directory drifts between sessions (docs/ → reports/ → /home/claude/)

Possibly Related

• #10580 (misspelled home directory)
• #14313 (wrong location in containerized environments)

However this is distinct: the model is not misspelling a path, it's using an entirely different filesystem root that doesn't exist on the user's Windows machine.