Q: When opening a virtual machine in VMware Fusion I get the error " Could not open dev vmmon Broken pipe." How do I fix this?

Answer

This error message is due to the VMware kernel extension not being approved for use. This need to approve kexts (kernel extensions) was introduced in macOS 10.13 High Sierra. You will need to manually approve this kext in order for VMware Fusion to operate properly.

If you see this, you will need to navigate to System Preferences, choose Security & Privacy, and approve VMware's kernel extension by selecting the Allow option next to the message saying that system software from VMware was blocked. To do this, you will have to ensure you click the padlock icon on the bottom left of the window to allow changes.

What if I don't see the button to allow the kernel extension?

In some cases, after installing VMware Fusion, the button to "Allow" the kernel extension to be used will not appear. You can also approve kernel extensions by booting into recovery mode.

1. Startup the Mac in recovery mode..
2. Click the Utilities menu and select Terminal.
3. Enter the following command:
   /usr/sbin/spctl kext-consent add EG7KH642X6
4. Press Enter.
5. Close the Terminal app, and restart.

Reinstalling VMware Fusion Pro

In some cases this error may be resolved by reinstalling the application. If your computer is managed by Jamf Pro you may be able to resolve this error by reinstalling the app running following command from the terminal: