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Logging

When enabled, the standard output and error of QEMU will be redirected to a log file stored in the .utm bundle. This is useful for debugging issues as well as submitting bug reports. If the log file exists, you can also export it out of the .utm bundle.

The debug log can contain personally identifying information including the names of mounted drives and key strokes. Make sure to check the contents before sharing the log with anyone.

Tweaks

These are advanced options for tweaking QEMU. Most users do not need to change any of the defaults.

UEFI Boot

Currently UEFI support is limited to i386, x86_64, arm, and aarch64 systems. Some operating systems such as older versions of Windows do not support booting from UEFI and this option can be disabled.

RNG Device

This emulates a random number generator that can be used by the guest operating system for cryptographic tasks. Some guests do not work properly with QEMU’s RNG device and this option can be disabled in those cases.

Balloon Device

The balloon device allows the guest operating system (with supported drivers) to more intelligently request RAM from the host. This is highly recommended.

Use Hypervisor

When the target architecture matches the host, you can use the hypervisor to enable virtualization. This allows the host to natively execute the guest instructions without having to re-compile and translate the code. If virtualization is not supported, this option does nothing and will fall back to emulation.

iOS This option is not supported on most installations. See the install guide for more details.

Use local time for base clock

This specifies the -rtc base=localtime option in QEMU. This synchronizes the guest clock to the local clock without any offsets. On some Linux guests, the RTC base is expected to be UTC and so this option should be disabled.

Force PS/2 controller

Only applicable to i386/x86_64 system guests. By default, the built-in PS/2 controller is disabled to prevent collision with the emulated USB input devices. However, some older operating systems do not support USB and so enabling this will allow input to be passed through the PS/2 device. When the PS/2 input is used, the only support mode of cursor input is iOS “drag cursor” or macOS “capture cursor”.

QEMU Machine Properties

For advanced users who wish to append additional -machine QEMU arguments. Note that default -machine properties are generated by UTM to work best with the guest system. When a custom machine property is specified, if it overlaps with one of the default properties, it will be overridden. Otherwise, it will be appended to the custom properties.

QEMU Arguments

This area allows you to quickly see what QEMU arguments the UTM configuration resolves to. This is not recommended for typical users. When debugging UTM issues, it is often helpful to try to reproduce the issue in QEMU and the “export” action allows you to get a text dump of the arguments.

UTM uses a customized fork of QEMU and therefore not all arguments will be supported in a vanilla QEMU installation. Additionally, if you wish to run QEMU with the generated arguments, you may want to remove the SPICE arguments and replace it with a different frontend.

At the end of the argument list is the option to add additional QEMU arguments. You should use quotes to escape spaces in any additional argument. This option is provided only for debugging purposes and the functionality may change or be removed in the future.