Help

The most common problems, and the exact fix for each.

Mac says it "can't verify" Tandem

Tandem isn't signed by Apple yet during the beta. Click Done (not Move to Trash), then open System Settings → Privacy & Security, scroll down and click Open Anyway next to Tandem. You only do this once. Step-by-step guide

Or, after moving Tandem to Applications, run this in Terminal: xattr -dr com.apple.quarantine /Applications/Tandem.app

Tandem opens but never finishes starting

Tandem waits up to 30 seconds on first launch, then says what went wrong. Quit it (⌘Q) and open it again. If it still fails, make sure Tandem is in your Applications folder, not running from Downloads or the zip file.

"Tandem needs git"

On a Mac, click Install git in the setup checklist, or run xcode-select --install and wait for Apple's installer to finish. On Linux: sudo apt install git (or your package manager's equivalent). The checklist ticks it off by itself.

My agent isn't found

Tandem looks for agents installed on your computer. Install one from Terminal, for example Claude Code: curl -fsSL https://claude.ai/install.sh | bash. The setup checklist and the Agents tab show the right command for every agent. New agents appear without restarting Tandem.

Open the Agents tab and click the agent's sign-in button. Finish signing in in your browser, then come back to Tandem. Each agent uses your own subscription.

"Hit its usage limit"

Your agent's subscription has run out for now. If you have another agent or account set up, Tandem moves the work there and carries on. Choose which ones it may use in Settings → Auto can use. Otherwise, wait for your plan to reset, or add another account from the Agents tab.

"npm: command not found" or "permission denied"

npm comes with Node.js: install it from nodejs.org, or use Claude Code's installer, which doesn't need npm. If npm says permission denied, install into your home folder: npm install -g --prefix ~/.local @openai/codex. Tandem finds it there.

Sign-in opens Google in your browser. Finish there, and let your browser open Tandem again when it asks. If nothing happens, check your internet connection, quit Tandem (⌘Q), open it and try again. Your projects and agents stay on your computer either way.

An invite link doesn't work

Sign in to Tandem first, then open the link again. If Tandem says it isn't a Tandem invite link, the link was cut off when it was copied: ask your teammate to send it again (in Tandem: the share button in the project's room makes and copies a fresh one).

A project won't open

Tandem saves work with git, so it may ask "Make this folder a git project?". Say yes: it saves your files as the first version, leaving out .env files and node_modules. Nothing is uploaded. If the folder has no commits yet, Tandem says so and offers the fix.

"Tandem isn't allowed to open that folder"

Open System Settings → Privacy & Security → Files and Folders and turn on Tandem. Or keep your projects outside Desktop, Documents and Downloads.

"The project folder was moved or deleted"

Tandem can't find the folder where it was. Move it back, or open it again from its new place with Open a folder. Unfinished work from the old place can't be saved; discard it.

An update didn't install

Updates only work when Tandem is in your Applications folder. Move it there, open it, then choose Tandem → Check for Updates. Still stuck? Download the latest version from the download page and replace the old app; your projects stay.

Linux: "Node.js is too old"

Tandem on Linux needs Node.js 22.18 or newer; it tells you which version it found. Install the current version from nodejs.org or with nvm: nvm install 22. Then open Tandem again.

Linux: the AppImage won't start

Right-click it, choose Properties and turn on Allow executing file as program. On Ubuntu 22.04 and newer it also needs sudo apt install libfuse2t64 (on 22.04: libfuse2). The .deb doesn't need either.

Still stuck?

Ask on the Tandem Discord, or send feedback from inside Tandem (account menu → Send feedback). We read everything.