Whatsapp Desktop App not showing QR code

Thanks for posting in the Apple Support Communities domcaz,

The following suggestions often lead to a solution for issues isolated to a specific app:

• If an app doesn’t quit as expected, or it’s unresponsive, you can force quit the app (you may lose unsaved changes). Choose Apple menu  > Force Quit, select the app in the dialog that appears, then click Force Quit.

• If the app quit, reopen it by clicking Reopen in the dialog that appears.

• Restart your Mac by choosing Apple menu > Restart.

• Make sure the app is compatible with your version of macOS.

• Open another file in the app. There may be a problem with the original file.

• Check for updates to your software.

• Disconnect any peripheral devices you just connected (for example, a printer). They may not be compatible with your version of macOS.

• Uninstall any app plug-ins or enhancements from other manufacturers.

• If you recently updated the app or macOS, a plug-in or enhancement you installed may no longer be compatible.

• Diagnose problems with your Mac to learn whether hardware you installed, such as additional memory, is incompatible, improperly installed, or defective.

If an app freezes or quits unexpectedly on Mac

If the issue persists, we recommend contacting the app developer, who may be able to provide additional guidance specific to the app: How to contact an app developer

Cheers!