Resolve Tejus launch, window, update, and reinstall problems on Windows without deleting useful state.

Treat the desktop application, its local backend, and the installed provider runtimes as separate layers. A window problem does not automatically mean your repositories, provider credentials, or Tejus workspace data are damaged.

Tejus ships for Windows x64 only. For download, SmartScreen, uninstall, and data locations, see Installation.

Tejus will not launch

Work through these checks in order:

Confirm you are on 64-bit Windows and installed tejus-setup.exe from the official download page.
Check Task Manager for a Tejus process left over from an earlier launch. Tejus runs as a single instance, so launching it again only brings the existing window forward.
Start Tejus again from the Start menu.
Restart Windows if a previous process cannot be ended cleanly.
Re-download the current installer from the official download page.
Run the installer over the current installation. It installs for your user account only (no administrator prompt) and keeps your data.

Windows protected your PC

The installer is signed by PRASANVI CYBER SECURITY SOLUTIONS PRIVATE LIMITED. A new release can still trigger SmartScreen for a short while. If the installer came from the official download page and More info shows that publisher, select Run anyway.

Do not delete data as a first step

Reinstalling the application and deleting Tejus's local data are different operations. Uninstalling or reinstalling keeps your data in %USERPROFILE%\.tejus and %APPDATA%\tejus. Preserve repositories, uncommitted changes, task evidence, and these folders before considering destructive cleanup.

Tejus shows a startup error

When the window opens but Tejus cannot start its local backend, it shows a dialog instead of a loading screen that never finishes:

Dialog	What it means	Buttons
Tejus's backend didn't start	The local backend failed to start several times in a row	Try again · Open logs · Quit
Tejus is already running elsewhere or Tejus could not verify database ownership	Another Tejus app or process is using the same data, or a lock was left by an interrupted start	Try again · Open logs · Quit
Tejus's window stopped	The window's renderer process exited	Reload · Open logs · Quit

Open logs opens the logs folder (%USERPROFILE%\.tejus\userdata\logs). Close any other Tejus process that uses the same data, then choose Try again. The database-lock dialog states that your data has not been changed. See Diagnostics for what each log file contains.

Do not expose or forward Tejus's local backend ports as a troubleshooting shortcut.

Closing while chats are still running

When quitting would interrupt running or connecting chats, Tejus lists those chats before closing.

Choose Cancel to keep the app and current work open.
Choose Quit to stop the listed work and close.
Leave Resume chats automatically enabled when eligible chats should receive a continuation turn on the next launch.

Automatic resume is guarded rather than unconditional. Tejus skips a remembered chat when it completed, was archived or deleted, already started newer work, or no longer belongs to a live project. If the local backend cannot record the resume intent within the bounded quit wait, Tejus falls back to interruption and still closes; do not assume that work will resume automatically.

The checkbox choice persists for later quits. Review it when a task must not continue without fresh supervision.

The window is blank or unresponsive

A blank window can come from the renderer, the local backend, graphics state, or a process left over from an earlier launch.

Wait briefly for initial startup and provider-health checks.
Close Tejus and confirm in Task Manager that no Tejus process remains.
Start it again with no other Tejus instance running.
Disable unusual display, proxy, or security software only when you can do so safely and reversibly.
Record whether the window is blank immediately or only after opening a specific project or surface.
Note the Tejus version and exact time before restarting again.

When only one project or task triggers the problem, report that boundary. It is more useful than "the app is blank."

The title bar looks wrong

Open Settings → Appearance and toggle Use custom title bar to switch between Tejus's frameless title bar (the default) and the standard Windows title bar. The change applies after a restart; use the Restart button that appears after you change it.

How updates work

Tejus updates itself from Tejus's own update feed:

It checks about 15 seconds after launch, every 6 hours, and when you come back to the window after a while.
A new version downloads in the background. While it downloads, an update button with progress appears at the bottom of the left rail, and the notification bell in the window bar shows Tejus version is available.
When the download is ready, select the update button or Install & restart in the bell. Tejus restarts into the new version.
Updates are never installed silently when you quit, and Tejus never installs an older version over a newer one.

There is no separate Beta update channel. To check manually, open the Editor view and choose Help → Check for Updates... in its menu bar, or restart Tejus and wait a few seconds. If you use the standard Windows title bar, you can also press Alt to show the window menu and choose Help → Check for Updates... there.

If Help → Check for Updates... reports that automatic updates are turned off because SYNARA_DISABLE_AUTO_UPDATE is set, remove that environment variable and restart Tejus.

The update failed

Preserve important Git work.
Close active provider turns and terminal processes when practical.
Select the update button again; a failed download or install can be retried from there.
If it still fails, quit Tejus, start it again, and let the next check prepare the update once more.
After repeated failed installs, Tejus shows Download the update manually with a Download manually button. Download the newest installer from the download page and run it over the existing installation.
Launch Tejus and confirm the version in Settings → System tools → Version before resuming important work.

An update failure does not mean local task data was deleted. Avoid combining an update recovery with manual data-folder cleanup.

Providers changed after an update

The Tejus update and provider CLI updates are independent. After updating Tejus:

Restart the app so provider discovery runs against the current environment.
Check each enabled provider's detected executable and authentication state under Settings → Agent providers.
Remove stale custom binary paths.
Update the provider runtime through its own supported method when Tejus reports that it is outdated.
Start a new provider session when protocol or capability negotiation changed.

Continue with Provider troubleshooting.