How to Troubleshoot Fusion startup issues
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How to Troubleshoot Fusion startup issues


Article ID: 323160


Updated On:




This resource provides troubleshooting steps for common Fusion startup issues such as:
  • A license expiration message appears
  • You are asked to register VMware Fusion every time you start it
  • You see errors similar to:
    • "Could not open /dev/vmmon: No such file or directory"
    • "Failed to connect to peer process"
    • "Cannot find a valid peer process to connect to"
    • "Failed to lock main memory file"
    • "The following install step failed: run postflight script for VMware Fusion. Contact the software manufacture for assistance"
    • "Error: Module version mismatch 4 != 5. Please update host. Failed to connect virtual device Ethernet0"
    • "Cannot find a serial number to unlock this version of VMware Fusion"
    • "Version mismatch with vmmon module"

Note: This article applies only to Fusion start-up issues. It does not discuss Windows or Linux start-up issues. The steps described here help if you are unable to open the Fusion application itself. If Fusion starts, but you cannot start a virtual machine, see Troubleshooting Fusion virtual machine startup issues (1014534).

If Fusion itself cannot start, there may be a problem with the application.

For more information, see Supported host operating systems for VMware Fusion and VMware Fusion Pro (2088571)


To troubleshoot this issue, attempt each of the following steps, and then try to open Fusion again:

  1. Restart your Mac
  2. Reinstall Fusion
  3. Repair the disk permissions (run First Aid on the Mac hard disk using OS X Disk Utility)

Restart your Mac

To begin troubleshooting this issue, restart your Mac. If, after the Mac restarts, Fusion still presents the same error, manually reinstall Fusion.

Reinstall Fusion

To manually reinstall Fusion:

  1. Uninstall VMware Fusion. For more information, see Manually uninstalling VMware Fusion (1017838) . This article contains a video that may be helpful.

    Note: This procedure does not affect the contents of your virtual machine.
  2. Download and install the latest version of Fusion from the VMware Fusion Download Center. For more information, see Downloading and installing VMware Fusion (2014097).

    Note: A VMware Fusion serial number obtained from VMware is required to complete installation. If you do not have your Fusion serial number (license key), see Viewing license keys in Customer Connect (2006831).
  3. Install or update VMware Tools in all of your virtual machines. For more information, see Overview of VMware Tools for VMware Fusion (1022048).

Repair the disk permissions (First Aid)

If VMware Fusion start-up problems persist, run the first aid on the Mac hard disk using OS X Disk Utility, then restart your Mac again.

To run first aid:

  1. Open the /Applications/Utilities folder.
  2. Double-click Disk Utility.
  3. Select the system hard drive (usually called Macintosh HD).
  4. Click First Aid.

Additional Information

For translated versions of this article, see:

Additional Information

Installing VMware Fusion triggers System Extension Blocked notification on Mac OS 10.13 High Sierra and above