CoApp not-recognized

DownloadHelper CoApp - Troubleshooting

If the coapp is not recognised by the extension, here are a few things you can try:

• Try the latest coapp. You will find the download links here.
• If you use Edge, make sure to install the addon from the Microsoft store, not the Google store. See relevant link here.

If you’re reporting an issue, please read this first

Make sure to read this document thoroughly. The answer of your problem is most likely in here. If you can’t find a solution to your problem, please report it, and include these information:

If the app is not recognized:

• The browser you’re using (be as specific as possible)
• OS (Linux/Windows/Mac) & OS version
• OS 64bits or 32bits
• Link to the coapp you installed
• On Mac, the output of /Applications/net.downloadhelper.coapp.app/Contents/MacOS/vdhcoapp --info
• On Windows, open a CMD shell, go to the install directory, and type vdhcoapp.exe --info
• On Linux, your sandbox mechanism (if any): flatpak/snap/…
• On Linux, the output of /opt/vdhcoapp/vdhcoapp --info (or ~/.local/share/vdhcoapp/vdhcoapp --info if it was install with the script)

If the download video is not valid or missing audio:

• version of Video DownloadHelper addon
• link to the page with the video

Windows

Make sure you use Windows 64 bits, with Firefox 64 bits, with CoApp 64 bits, or Windows 32 bits, with Firefox 32 bits, with CoApp 32 bits.

You can check where the CoApp registered its manifests. Run these commands in a CMD prompt:

For 64 bits system:

reg query HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Mozilla\NativeMessagingHosts\net.downloadhelper.coapp

For a 32 bits system:

reg query HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\NativeMessagingHosts\net.downloadhelper.coapp

If this returns nothing, something was wrong during the coapp installation process.

If this returns something, but it doesn’t point to an existing file, re-install the CoApp.

If this return something, and it does point to an existing file, your Firefox might be using the wrong architecture.

Windows - Antivirus

It’s possible that your Antivirus blocks the CoApp. Sadly, Antivirus can be overly protective. Our application is OpenSource, and not malicious in any way, you can look at the source code right here. Video Downloadhelper has been validated by Google, Microsoft and Mozilla organizations. We recommend either:

• using the Microsoft Antivirus - it is free and recommended by Microsoft;
• or allowing the CoApp (you’ll need to allow the 3 “.exe” files located in the installation directory).

Windows - Installation Error

If you’re getting an error during installation, try installing after closing your browser (Firefox, Chrome, Edge).

Mac

After install, start the coapp (only one time after installation), this should re-register the app in the relevant browsers. If you use an old version of MacOS, see this.

Ubuntu (and Flatpak / Snap based systems)

First, make sure Ubuntu and Firefox are up to date. Firefox 122 on Ubuntu 22.04 had an issue that has been recently fixed.

Most of the time, the issue is a missed prompt. Firefox should have showed you a prompt to allow the coapp to communicate with the extension. Some people miss the prompt, or the prompt just never shows up. There’s no user interface to change that setting. To solve this, run these commands (even if you don’t use Flatpak):

~/.local/share/vdhcoapp/vdhcoapp install
# or (depending how it was installed)
/opt/vdhcoapp/vdhcoapp install # (not as root! Don't use sudo)

Followed by:

sudo apt-get install -y flatpak
flatpak permission-set webextensions net.downloadhelper.coapp snap.firefox yes

Firejail-based systems

See this comment.

KDE Neon (and AppArmor based systems)

Add /opt/vdhcoapp/vdhcoapp ux, to /etc/apparmor.d/local/usr.bin.firefox.

Then restart apparmor.service and Firefox.

Linux (all)

• To re-register the app, run;

~/.local/share/vdhcoapp/vdhcoapp install
# or (depending how it was installed)
/opt/vdhcoapp/vdhcoapp install # (not as root! Don't use sudo)

• To run diagnostics:

~/.local/share/vdhcoapp/vdhcoapp --info
# or (depending how it was installed)
/opt/vdhcoapp/vdhcoapp --info

• do not install vdhcoapp within the /usr/ directory, it won’t be detected by your browser. See here why.