VMware Fusion on macOS High Sierra – System Extension Blocked

This is just a quick post about an issue you’ll see when installing VMware Fusion on macOS High Sierra.

During the install the following screen pops up.System Extension Blocked








As you’ll have to dismiss that screen for continuing I figured it might be helpful to give quick directions.

The “Security & Privacy System” preferences can be found in the system preferences (apple menu -> system preferences)

security & privacy


Just select that one and you’ll get the screen that the popup was telling you about.

Allow VMware extensions


Now click the Allow button here and you’re all set.








Update 2017/10/03 Sometimes it turns out that the button does not show up. You get error “Cannot find a valid peer process to connect to” but no way to fix it. Turns out that there was a smart cookie that managed to figure this one out. See:  https://communities.vmware.com/message/2708220#2708220

In short: You can trigger the confirmation by moving the Fusion install to another folder -while using Finder- and then back into the Applications folder.

Update 2017/10/30

Another reason for not being able to install is if gatekeeper has quarantined the downloaded installer. You can find out via the command line. Assuming your files are downloaded to the normal download folder, running the following commands using terminal:

xattr -l ~/Downloads/VMware-Fusion-10.0.1-6754183.dmg

xattr -dr com.apple.quarantine ~/Downloads/VMware-Fusion-10.0.1-6754183.dmg

The first command xattr -l lists the .dmg file extended attributes and the command xattr -dr removes the quarantine flags (-d = delete -r = do for all files within the dmg)

After doing that rerun the installer to install VMware Fusion again.

Author: Wil van Antwerpen

Wil van Antwerpen is a software developer who loves to work on Open Source and dabble a bit with VMware products. He likes to help people out as that is a good way to learn more. He is the author of Vimalin Backup (https://vimalin.com) which is virtual machine backup software for VMware Fusion and VMware Workstation Pro.

4 thoughts on “VMware Fusion on macOS High Sierra – System Extension Blocked”

  1. Hi.

    FYI, none of this worked for me. No matter how many times I reinstalled, moved the application, downgraded to a previous working version, etc, the “Allow” button never turned up in Security & Privacy and I continued to get the “Cannot find a valid peer process to connect to” error.

    What finally did work was completely disabling the “Kernel Extension User Consent”, as suggested by efengle here: https://communities.vmware.com/message/2713548#2713548.

    1. Restart Mac. Hold Command+R at the startup chime until you see the Apple logo. This will boot into the Recovery OS
    2. Top Menu, Select Utilities -> Terminal
    3. In Terminal, check the status Kernel Extension User Consent via “spctl kext-consent status”. The output should say “ENABLED”.
    4. To Disable, type “spctl kext-consent disable”
    5. Close Terminal. Restart.

    Obviously disabling security features is not the ideal solution, but for now it is the only thing that has worked for me, so I’ll take it. Hopefully it can help someone else as well.

  2. Hello “Argh” as you say that should not be needed. Was this with VMware Fusion 10 or with an earlier version? Earlier versions might require you to -at least temporary- disable kernel extension user consent.

    1. Hi Wil.

      Apologies for the delayed reply. I had tried with many versions, including VMware Fusion 10.1.1.

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