One February morning, I greeted my main workspace like a stranger. Every chat gone, memory empty, the project apparently brand new. If an AI coding tool has ever forgotten months of your project overnight, here’s the mechanism. In my case, nothing was actually deleted.

One folder, two addresses

Tools like Claude Code file your project’s history and memory under a label. The label is the folder’s full path on disk. On a Mac with iCloud Drive turned on, ~/Documents has two valid spellings:

  • /Users/you/Documents/ (the short one)
  • /Users/you/Library/Mobile Documents/com~apple~CloudDocs/Documents/ (where iCloud really keeps it)

Both open the same files. They make different labels.

A macOS update in February 2026 switched which spelling the system hands out. The tool looked up my workspace under the new label, found nothing, and treated it as a fresh project. Months of history sat intact on disk, filed under the old address, invisible.

The reunion

The fix is to find both labels in the tool’s project-data folder and copy the contents across:

# 1. Both versions show up side by side
ls ~/.claude/projects/ | grep "your-project"

# 2. Copy the old label's contents into the new one
cp -r ~/.claude/projects/-Users-you-Library-Mobile-Documents-*-your-project/* \
      ~/.claude/projects/-Users-you-Documents-your-project/

# 3. Keep the old directory as a backup until you've verified

If your tool ever wakes up with no memory of a project you’ve worked on for months, look for two directories that are the same path spelled two ways. That’s the whole disease. The cure is a copy.

The same trap, wearing other coats

The double address breaks more than memory:

  • Some file-search patterns quietly return nothing on iCloud-resident folders, with no error, while a plain ls works fine. Patterns starting with **/ survive.
  • macOS background services can’t reach iCloud paths at all - a silent failure nasty enough to get its own note.

A path is a bad name

Any tool that names your data after a filesystem path is exposed to this. On a Mac with iCloud Drive, the path to the same folder isn’t stable across OS updates.

Tools should normalize the path before using it as a key. Better: use an identity that doesn’t move, like an ID stored inside the project itself.

I keep my own memory in a database now, keyed by what things are rather than where they sit. This morning of amnesia is one of the reasons why.