# Troubleshoot host computers and virtual machines

This information provides troubleshooting steps for common technical issues.

## Fix network failures in the Ubuntu VM

Occasionally, network failures may occur in the Ubuntu VM while the host computer has no network issues. Any ongoing compilation in the Ubuntu VM may result in fetch failure.

To re-establish the network in the Ubuntu VM, do the following:

1. To find the corresponding network interface, run the `ip link`
command in the Ubuntu terminal window.

    The Ubuntu terminal window returns a network interface. For example,
enp0s1.
2. To re-establish the network in the Ubuntu VM, use the network interface and run the following commands:

ip link set dev <network_interface> down
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ip link set dev <network_interface> up
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    For example:

    `ip link set dev enp0s1 down`

    `ip link set dev enp0s1 up`

## Optimize slow or unresponsive Mac host computer

If the Mac host computer is slow or unresponsive, the UTM VM may be consuming all the available resources of the host computer.

To troubleshoot this issue, do one of the following:

- Use the recommended settings to reconfigure the memory and CPU core
allocation for the Ubuntu VM. For instructions, see Step 5 in the following:

    - [Create a VM in UTM on an Arm64 Mac](https://docs.qualcomm.com/doc/80-80022-41/topic/set-up-an-ubuntu-vm-on-an-arm64-based-mac.html#create-a-vm-in-utm-on-an-arm64-based-mac)
    - [Create a VM in UTM on an x86\_64 Mac](https://docs.qualcomm.com/doc/80-80022-41/topic/set-up-an-ubuntu-vm-on-an-intel-based-x86-64-mac.html#create-a-vm-in-utm-x8664-mac)
- Reconfigure the Ubuntu VM settings such that the Ubuntu VM and the
host computer use the available resources optimally. For example,
distribute the memory and CPU cores equally among the host computer
and the VM.

    Also, avoid running CPU-intensive tasks on the host computer
when you are using the Ubuntu VM.

Last Published: Apr 28, 2026

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