Windows installer falsely reports “Attu cannot be closed” when upgrading to v3.0.0-beta.6 #1027

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1. shanghaikid commented on Sep 3, 2026

   

   shanghaikid

   on Sep 3, 2026

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   Thanks for the detailed investigation. You were correct that the beta.6 installer used an older electron-builder version.

   The Attu v3.0.0 stable release is built with electron-builder and app-builder-lib 26.15.3, which includes the upstream process-detection fix introduced in 26.13.0.

   Please try upgrading with the latest v3.0.0 Windows installer. If the installer still incorrectly reports that Attu is running, please let us know the installer filename and any similarly named processes on the system.
2. grassfish1122 commented on Sep 11, 2026

   

   grassfish1122

   on Sep 11, 2026

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   Thanks for the update. I tested again with the stable v3.0.0 installer.

   Installer filename: attu-3.0.0-x64.exe

   Before installation

   Before launching the installer, I verified that there was no running Attu.exe process and no other Attu-related process on the system.

   

   During installation

   However, after launching attu-3.0.0-x64.exe, the installer still reports:

   Attu cannot be closed. Please close it manually and click Retry to continue.

   

   While this dialog was still open, I checked the running processes again:

   

   There is still no running Attu.exe.

   The only Attu-related executable/process appearing after installation starts is the installer itself, attu-3.0.0-x64.exe.

   So the issue is reproducible with the stable v3.0.0 installer even though no existing Attu application process is running before the installation starts.

   Could the installer itself still be matched by the process detection logic because its filename contains attu?
3. shanghaikid commented on Sep 11, 2026

   

   shanghaikid

   on Sep 11, 2026

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   Thanks for retesting and for the detailed process checks. Our earlier suggestion to upgrade the installer did not cover every part of the upgrade path—sorry about that.

   We checked the NSIS installer code. The newer process-name check uses an exact match for Attu.exe, so the filename attu-3.0.0-x64.exe alone should not trigger that check. However, an upgrade still runs the previously installed version's uninstaller, which retains its original logic. The installer also displays this same “Attu cannot be closed” message after repeated failures of the old uninstaller, so the message does not necessarily mean an Attu.exe process is running. We have not yet confirmed which path is failing on your machine.

   Suggested workaround: uninstall the old version first, then install v3.0.0.

   1. Cancel the installation and close Attu and all Attu installer windows.
   2. Back up Attu's local settings/data folder before uninstalling. With the standard Windows configuration, check %APPDATA%\attu (you can paste this into File Explorer) and copy the folder somewhere safe if it exists. Also back up any files you have manually stored inside the custom installation directory. Do not delete the AppData folder as part of this workaround.
   3. Open Windows Settings → Apps → Installed apps (or Apps & features) and uninstall the existing Attu version. If offered an option to remove application data, leave it unchecked. For the previous all-users installation, allow administrator elevation when prompted.
   4. After uninstalling successfully, restart Windows. Place attu-3.0.0-x64.exe in a folder outside the old installation directory, such as Downloads, and rename it to setup.exe as an additional precaution for older detection logic.
   5. Run setup.exe and install Attu into the default directory. This gives you a fresh application installation while retaining the local data you backed up; resetting local settings is not required for this workaround.

   If step 3 also fails, please stop there rather than manually deleting installation folders or registry entries. As an alternative, you can use the Windows x64 ZIP build from the v3.0.0 release: extract it into a new folder outside the existing installation and run Attu.exe. This bypasses the NSIS installer/uninstaller path.

   If the issue persists, please share the old installation directory, the full path where you launched the installer, and whether uninstalling Attu separately succeeds (including any error shown). Those details will help distinguish an old-uninstaller failure from the remaining path-based process check.