One saves to the cloud. Two save locally in hidden folders Windows doesn’t show you. If your laptop breaks, you could lose everything.

Yesterday my laptop keyboard decided to play silly buggers. The keys started sticking and doing random things, I found out what the cause was but had to close down and leave it for some time.

Meanwhile I started asking myself, where does Claude actually store my work?

The answer took most of this morning to find, and what I found should concern anyone using Claude Desktop on Windows for serious work.

Three tabs. Three completely different behaviours. This is specifically for Windows Mac and Linux may be different.

Claude Desktop on Windows has three tabs: Chat, Cowork, and Code. Most people assume they all work the same way, they do not.

Chat saves your conversation history server-side, on Anthropic’s servers. If your laptop dies, your Chat sessions are safe, log in from any machine and they are there.

Cowork stores your session history locally on your machine, in a hidden folder buried inside Windows AppData. If your laptop dies before you back that folder up, those sessions are gone. Harmonic Security’s independent security review of Cowork confirms this: conversation history is stored on the user’s machine, is not subject to Anthropic’s retention policies, and cannot be centrally managed or exported.[1]

Code stores session history locally too, as JSONL files in a hidden .claude folder. There is an additional complication: the storage path changed in a product update in February 2026, and users lost access to all their previous sessions from the sidebar without any migration running automatically.[2]

Three tabs. Three different answers to the question “where is my work?”

The folder Windows doesn’t show you

On Windows, Cowork stores your session history here:

C:\Users\YourUsername\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\local-agent-mode-sessions

AppData is a hidden folder. Windows does not show it by default. You have to enable “Show hidden items” in File Explorer to find it, or paste the path directly into the address bar.[3]

Most people never look, know, or find out the hard way, which is almost what happened to me yesterday.

Here is what I found when I tried to access that folder from inside a Cowork session:

Verbatim from CoWork.

“Interesting - that’s blocked. Even I can’t see that folder from inside Cowork. Which actually validates your point: this data sits in a place neither the user nor Claude can casually browse to.”

Claude, inside Cowork, tried to access its own hidden session folder. It was blocked, that is not a metaphor, it’s a live demonstration of the governance gap.

This is not a bug. It is a design assumption.

Anthropic did not set out to hide your work from you. This is how Windows manages application data: the program lives in Program Files, and your personal data lives in AppData. Claude Desktop follows that convention. Microsoft’s rules, Anthropic’s app.

The problem is not the convention. The problem is that nobody tells you about it when you start using Claude for work that matters.

The official Claude Desktop documentation covers installation, system requirements, and MCP server configuration. It does not contain a plain-English explanation of where each tab stores your session history, what happens if your machine fails, or how to back it up.[4]

That gap is what costs people work.

What about Mac and Linux users?

This article covers Windows specifically because that is where I found the issue. Mac and Linux users should check their own paths before assuming they are safe.

On Mac, Cowork session history sits at: /Users/YourUsername/Library/Application Support/Claude/local-agent-mode-sessions

On Linux, Claude Desktop is not officially supported, so if you are running it, you are already operating without a safety net.

The storage behaviour may differ across operating systems and app versions. Check your own machine. Do not assume.

What this has to do with methodology

I had been building toward platform-agnostic working for exactly this reason. The goal was a portable governance layer that travels across machines. The point of contAIn™ as a methodology layer that directs AI is precisely this: you govern the system before the system surprises you, working toward defined outcomes rather than hoping the tools behave.

I had most of it, and I do regular backups anyway, but the point is it was not completely done.

The keyboard breaking was not the disaster. The disaster would have been if I had not already been thinking about disaster recovery as a governance question rather than an IT question.

The tools do not tell you where they keep your work, that is not their job. Knowing where your work lives, governing your own data, building a system that survives the machine it runs on. That is the layer that was missing from AI before anyone built a methodology for it, and that is what humans above the AI loop actually means.

The backup that matters

If you are using Claude Desktop on Windows for serious work, do this now:

Enable hidden files in File Explorer (View > Show > Hidden items), navigate to AppData, and find the Claude folder. Back it up to an external drive or cloud storage. Do it before something breaks, not after.

For Code sessions, back up the .claude folder at C:\Users\YourUsername\.claude\, specifically the projects subfolder.

For Chat sessions, you do not need to do anything. They are already in the cloud.

Then ask yourself the governance question, my dodgy keyboard forced me to ask: if this machine stopped working tonight, where would my work actually be?

configure YOUR system. contAIn™ the chaos. control YOUR outcome.

References

[1] Harmonic Security, Securing Claude Cowork: A Security Practitioner’s Guide (March 2026): https://www.harmonic.security/resources/securing-claude-cowork-a-security-practitioners-guide

[2] GitHub, Claude Desktop update loses Code session history (February 2026): https://github.com/anthropics/claude-code/issues/29373

[3] How to Back Up and Migrate Claude Cowork Chat History: https://it-libero.com/en/for-it-specialist/4511

[4] Anthropic, Install Claude Desktop (Support): https://support.claude.com/en/articles/10065433-install-claude-desktop

Samantha Maeer | Founder and Creator, contAIn™ | 30 years operating at the sharp end of tech and project management across the UK, Southeast Asia and the Middle East. Creator of the strategic methodology layer that directs AI and puts humans above the AI loop. | contain.digital

This article was originally published on Substack.