Troubleshooting

First checks#

• Save the Scratch project and download a backup before reloading or changing installations.
• Compare both collaborators’ installed versions and server origins.
• Check API status, then confirm both accounts have completed Scratch Auth.
• Keep one editor tab per user for the project; avoid running multiple installed copies of CoBlocks.

No CoBlocks button in the editor#

• Use an installed and enabled desktop build, not an unopened ZIP.
• Allow the extension to run on Scratch, then refresh the Scratch page.
• Open an editable project that you own, or enter a collaboration through its invite/linked copy.
• Check the browser’s extension page for load errors. A Firefox temporary add-on must be loaded again after restarting.

Sign-in loops or unexpected logout#

• Scratch Auth and the current Scratch session must use the same account; capitalization differences alone are accepted.
• Another login to the same CoBlocks account replaces the previous session.
• Start a fresh handoff from the popup if it expired. Do not reuse old callback URLs.
• Changing server clears credentials. Sign in again on the chosen backend.
• If service/provider requests are failing, check status and wait before repeatedly attempting login.

Cannot add a friend or find a shared project#

• The friend must first sign in to CoBlocks on your server.
• Use the Scratch username, not a display name or profile URL.
• For direct sharing, the recipient should add the project owner to their friends list.
• For link sharing, finish accepting the current invitation; a replaced or seven-day-old link will fail.
• Ask the owner to check project access. Removed or expired backend records are not guaranteed to be recoverable.

No sync or no live cursor#

• Both users must be connected to the same CoBlocks collaboration, not independent projects with the same title.
• Use the online list to check connectivity and access.
• For pointers, both people select the same sprite and the Code tab, then move the mouse over the workspace.
• If a custom server connects over HTTP but not live sync, verify its Socket.IO/WebSocket proxy forwarding.
• A local recovery-only editor intentionally pauses live collaboration. Save that copy before trying to reconnect.

Missing chat notifications or sound#

• Enable Notifications and approve the browser permission; check system Focus / Do Not Disturb.
• Enable Ping Sounds separately and interact with Scratch to permit audio.
• Messages received while chat is open do not increase chat unread count.
• The small in-editor toasts disappear quickly; open the notification center to inspect current activity.

Backpack script does not appear#

• Drop a block stack onto CoBlocks Backpack, not Scratch’s personal backpack.
• Use Refresh, and check the status message for size/capacity errors.
• Select the destination sprite before using Add to sprite.
• Only the script’s creator and project owner can remove a stored item.

Project unavailable or recovered locally#

Keep the browser profile and existing editor intact. If CoBlocks loaded a local snapshot, save it to Scratch and download an .sb3 immediately. Do not clear storage or uninstall first. Local recovery cannot restore a snapshot that never existed in this profile.

Report an issue with useful details#

• Browser name/version and CoBlocks version shown in the popup.
• Whether the build is store, unpacked, or temporary Firefox.
• Public or custom server, which step failed, and the exact visible error.
• Minimal reproduction steps and screenshots with private information removed.