# Install the Treecat agent on Windows, Mac or Linux > Step by step: download the Treecat desktop agent from Settings → Agent, install it, sign in, and keep it online. Plus fixes for blocked Windows downloads. Source: https://wiki.treecat.io/install-the-treecat-agent · Section: The Treecat agent · Updated: 2026-10-22 In Treecat, open **Settings → Agent** and use **Download the agent**. Install it, sign in with the same Google account you use for Treecat, and leave it running in the background on a computer that stays on. Treecat shows the agent as online once it connects. You only need the agent for Poshmark, Mercari, Whatnot, Facebook Marketplace and Etsy. See [What is the Treecat agent?](https://wiki.treecat.io/treecat-agent-computer-on-24-7) ## Install the agent 1. If you used an older Treecat agent on this computer, uninstall it first. 2. Sign in to Treecat in a browser and open **Settings → Agent**. 3. Under **Download the agent**, click **Download for Windows** or **Download for macOS**. On Windows, the Microsoft Store version is recommended. A Linux build is also offered. Always download from this page so you get the current agent. 4. Open the download and follow the installer. On Windows, if the app asks to turn on virtualization, click **Enable & restart** and approve the prompt. See [Turn on virtualization](https://wiki.treecat.io/turn-on-virtualization) if it says virtualization is off in the BIOS. 5. Open the Treecat agent and click **Login**. A page opens in your browser: sign in there with the same Google account you use for Treecat. 6. Choose a performance mode: **Economy** uses the least memory, **Balanced** mixes speed and efficiency, **Performance** is the fastest and uses 8 GB. 7. Back in Treecat, refresh **Settings → Agent** and check that the agent shows as online. Leave it running in the background. ![Settings → Agent with the linked computers and their online status](https://firebasestorage.googleapis.com/v0/b/boomer-dff96.appspot.com/o/images%2Fwiki%2F2026-10%2Finstall-the-treecat-agent-0-ffb839e2.png?alt=media&token=0ee12dae-28e5-43da-8b08-620e94c02ae6) > **Note:** Each computer links separately and appears as its own row on Settings → Agent. Install the agent on the one computer that will stay on, and quit any copies you do not use. ## Next: connect your marketplaces With the agent online, go to **Settings → Marketplaces** and click **Add marketplace**. See [Connect your marketplaces](https://wiki.treecat.io/connect-your-marketplaces). ## How do I open the agent? - **Windows:** click the arrow on the taskbar to show hidden icons and click the Treecat icon, or open the Start menu, search for "treecat" and open the Treecat Agent app. - **Mac:** click the Treecat icon in the menu bar. - From the website: on **Settings → Agent**, the row for this computer has an **Open** or **Start** button. The agent window shows whether it is running and signed in, the performance mode, **Start at login**, and the **Sign Out**, **Reset** and **Quit** buttons. Leave **Start at login** on so the agent comes back after a restart. ## How do I update the agent? When a newer version is available, the agent window shows an update button (**Restart to update**), and Settings → Agent marks the computer with "update available". Click it and let the agent restart. If you see a prompt about updating the VM, you can safely close it. ## "Couldn't link your agent: device codes expire after 5 minutes" Open the agent, click **Login** again and finish the page that opens in your browser, making sure you are signed in to Treecat there. The code is valid for five minutes, so complete the step promptly. ## Windows blocks the download or the installer will not run - Installing from the **Microsoft Store** avoids most of these warnings. - In Edge or Chrome, open the downloads list and choose **Keep** for the file, then **Show more → Keep anyway**. The warning appears because the file is not yet widely downloaded. - If Windows says **"Windows protected your PC"**, click **More info**, then **Run anyway**. - If you see **"MSVCP140.dll was not found"**, install the Microsoft Visual C++ Redistributable from Microsoft, then run the installer again. - If you are still stuck, try downloading with Chrome, or book a call from the Help page. ## If the agent will not start or shows offline - Quit the agent completely from its menu-bar or tray icon, then open it again. - On Windows, check virtualization is on. See [Turn on virtualization](https://wiki.treecat.io/turn-on-virtualization). - Make sure the computer is not asleep and has internet. - Still stuck? On **Settings → Agent**, click **Copy agent details for support** (the copy icon on the computer's row) and email them to support@treecat.io. For more, see [The agent keeps going offline](https://wiki.treecat.io/agent-offline). ## Frequently asked questions ### Is the Treecat agent free? Yes. The agent is part of Treecat. You only pay when a billable item sells. ### Which operating systems are supported? Windows and macOS. A Linux build is also offered on Settings → Agent.