The problem
The Claude desktop app is signed in to one account at a time. If you have a personal plan and a work or Team plan, switching means signing out and back in, and you lose your place each time. Opening Claude in a browser tab works for one of them, but you give up the desktop app's features for that account.
You can't just open Claude twice, either: macOS brings the existing window forward, and Claude keeps a single profile with your login in it.
How to run a second Claude with Duplex
- Install Duplex (instructions below).
- Click "New Instance…" and pick
Claude.appfrom your Applications folder. - Name it "Claude Work" or similar. Pick the badge icon so you can tell the two apart in the Dock.
- Launch it. It opens signed out. Sign in with your second account using email or Google.
That's it. Your original Claude stays signed in to your first account, and "Claude Work" stays signed in to the second. Both open from the Dock and can run at the same time.
What you should know
- Sign-in goes to the right window. Claude's sign-in returns from your browser through a
claude://link. Because macOS treats each Duplex instance as a separate app, the link comes back to the copy you're signing in to. - Updates follow the original. Update Claude as usual. The instance rebuilds itself from the new version the next time it launches. Update prompts inside the instance can be ignored.
- Permissions are per copy. If you use Claude with your microphone or files, the instance asks for those permissions once on its own.
- Passkeys aren't supported inside an instance. Sign in with email or Google instead.
Get Duplex
Your first instance is free, forever. A $9 one-time license unlocks unlimited instances on up to 2 Macs. Requires macOS 13 or later.
brew tap bnimit/tap brew trust bnimit/tap brew install --cask duplex
Questions
Can I have two Claude accounts on one Mac?
Yes. Use the Claude desktop app for one account and a Duplex instance of Claude for the other. Both can be open at the same time, each with its own login and chat history.
Will my chats mix between accounts?
No. Each copy keeps its login and data in its own folder, so chats, settings, and connected tools stay separate.
Does a second copy take up double the disk space?
No. Duplex makes a copy-on-write clone, which shares its disk blocks with the original. Finder shows the full app size, but a Claude instance costs about 6 MB of real disk.
Does Duplex change the original app?
No. The original is never modified and keeps updating itself. Each instance follows its updates automatically the next time you launch it.
Is Duplex free?
Your first instance is free, forever, which is all you need for a second account. A $9 one-time license unlocks unlimited instances on up to 2 Macs. There is no subscription.
Is it safe?
Duplex is native Swift, notarized by Apple, and collects no analytics. The source is public on GitHub, so you can read exactly what it does.