Fixing "1Password Can't Connect to Browser Extension" on macOS

Recently I ran into an issue where 1Password's desktop app refused to connect to its browser extension. The usual fixes — signing out and back in, rebooting, even deleting and reinstalling the app — didn't help. Turns out a plain reinstall doesn't remove the leftover application data, caches, and the login-item helper that manages the native-messaging connection between the app and the browser. If any of that is stale or corrupted, a fresh install just talks to the same broken state.

The Fix: Full Cleanup Before Reinstalling

Quit 1Password and your browser completely, then clear out the following before reinstalling.

App support & data

~/Library/Application Support/1Password
~/Library/Application Support/1Password 7
~/Library/Group Containers/2BUA8C4S2C.com.1password
~/Library/Containers/2BUA8C4S2C.com.1password
~/Library/Application Scripts/2BUA8C4S2C.com.1password

Caches, preferences & saved state

~/Library/Caches/com.1password.1password
~/Library/Caches/2BUA8C4S2C.com.1password
~/Library/Preferences/com.1password.1password.plist
~/Library/Preferences/com.agilebits.onepassword7.plist
~/Library/Saved Application State/com.1password.1password.savedState
~/Library/WebKit/com.1password.1password
~/Library/HTTPStorages/com.1password.1password*
~/Library/Cookies/com.1password.1password.binarycookies

The actual culprit: the browser-connect helper

This is the piece most people miss. 1Password registers a login item ("1Password Extension Helper") that brokers the connection to the browser extension. If it's stuck in a bad state, no amount of app reinstalling fixes it — you have to remove it from System Settings → General → Login Items & Extensions, along with any leftover launch agent:

~/Library/LaunchAgents/com.1password*

A Script to Do It Safely

Rather than a hard rm -rf, move everything to Trash so it's reversible:

paths=(
  "$HOME/Library/Application Support/1Password"
  "$HOME/Library/Application Support/1Password 7"
  "$HOME/Library/Group Containers/2BUA8C4S2C.com.1password"
  "$HOME/Library/Containers/2BUA8C4S2C.com.1password"
  "$HOME/Library/Application Scripts/2BUA8C4S2C.com.1password"
  "$HOME/Library/Caches/com.1password.1password"
  "$HOME/Library/Caches/2BUA8C4S2C.com.1password"
  "$HOME/Library/Preferences/com.1password.1password.plist"
  "$HOME/Library/Preferences/com.agilebits.onepassword7.plist"
  "$HOME/Library/Saved Application State/com.1password.1password.savedState"
  "$HOME/Library/WebKit/com.1password.1password"
  "$HOME/Library/Cookies/com.1password.1password.binarycookies"
)

for p in "${paths[@]}"; do
  [ -e "$p" ] && mv -v "$p" "$HOME/.Trash/"
done

for f in "$HOME/Library/HTTPStorages/"com.1password.1password*; do
  [ -e "$f" ] && mv -v "$f" "$HOME/.Trash/"
done

for f in "$HOME/Library/LaunchAgents/"com.1password*; do
  [ -e "$f" ] && mv -v "$f" "$HOME/.Trash/"
done

One gotcha: if you run this more than once, mv can fail with "Directory not empty" because a same-named folder already sits in Trash from a previous run. Just empty the Trash between attempts, or rename the destination.

The Order That Actually Works

Quit 1Password and the browser entirely.
Remove the "1Password Extension Helper" from Login Items.
Run the cleanup script above.
Reboot.
Reinstall 1Password fresh, then reinstall/re-enable the browser extension.

After doing this, 1Password prompted for sign-in on first launch — a clear sign the stale state was actually gone — and the browser extension connected immediately afterward.

The lesson: on macOS, "delete and reinstall" only removes the .app bundle. Anything in ~/Library (support files, caches, containers, login items) survives a reinstall untouched, and for an app like 1Password that maintains a persistent local connection to a browser helper, that leftover state is often exactly what's broken.