Ubuntu 22.04.5 Desktop installer freezes immediately after confirming "Write changes to disk"

The Ubuntu installer freezes consistently, every attempt, right after clicking "Continue" on the "Write the changes to disk?" confirmation dialog. The "Install Now" button remains visible but greyed out, no progress bar ever appears, and the UI becomes unresponsive.

Despite the frozen UI, the QEMULauncher process shows sustained 200–250% CPU usage indefinitely (checked via `top` on macOS).

I enabled Debug Logging and captured full logs across multiple reproductions. Consistent pattern across all of them:

- VM boots, ISO mounts, guest agent connects — all normal
- Normal activity continues (mouse mode switches, display events) up to the point of freezing
- After that point, the log shows zero further activity of any kind — no QMP commands, no guest communication, no disk I/O, no errors, no warnings — except the SPICE cursor-spin animation being redrawn every ~18ms, indefinitely, until I force-quit.
- In one ~11-minute reproduction, this silent gap lasted the entire session. In a shorter ~5-minute reproduction, the same pattern appeared: a clean ~77-second gap with zero logged activity before I force-quit.

This suggests QEMU itself stays alive and keeps rendering the cursor (explaining the sustained CPU usage), but everything else — communication with the guest, disk I/O — has completely stalled, seemingly right around or shortly after the "write changes to disk" confirmation is sent to the guest.

**Ubuntu

[debug.log](https://github.com/user-attachments/files/31578034/debug.log)

Installer settings used:** Normal installation, with "Download updates while installing" and "Install third-party software" both unchecked — so the freeze happens with no network dependency involved.

**Note on Ubuntu 24.04:** I initially attempted this with Ubuntu 24.04, which had separate display/graphics issues (black screen / "display output is not active" during boot) — resolved at the time by switching the display card to a non-GL option. I then switched to 22.04.5 specifically to rule out 24.04-specific display quirks, and that's when I started hitting this distinct disk-write freeze instead.

**What I've tried (none resolved it):**
- CPU type: Default → max
- Disk interface: IDE → VirtIO (both tested, same result)
- CPU cores: tested at 2 and 8
- RAM: tested at 4096MB and 8192MB
- Display card: confirmed non-GL (virtio-gpu-pci / virtio-vga)
- Hardware OpenGL Acceleration: off
- Full macOS update: 14.0 → 14.8.9 (same result on both)
- Shared directory: reproduced both with and without one configured — no difference
- Verified ISO checksum against official releases.ubuntu.com SHA256SUMS — matches
- Tried "Try Ubuntu" (live session) separately — booted fine, no freeze there

**Configuration:**
- UTM Version: 4.7.5 (118)
- Installed via: Homebrew
- macOS Version: 14.8.9 (also reproduced on 14.0)
- CPU type: max
- Mac: 2020 MacBook Pro, Intel Core i5 (Quad-core), 16GB RAM, Intel Iris Plus Graphics
- Guest: Ubuntu 22.04.5 Desktop (amd64), fresh VM each attempt

I searched existing issues/discussions and found similar-sounding freezes, but they're primarily on Apple Silicon (M1) and typically occur on reboot after install rather than during the initial disk-write step — this appears to be a distinct case.

Start by reproducing the freeze in UTM 4.7.5 with the stated Ubuntu 22.04.5 configuration, then inspect the supplied debug.log around the “Write changes to disk” confirmation and the QEMULauncher process behavior. No source file or test is named; done means identifying the stalled path and confirming that installation proceeds normally after the fix.

Written by the indexing model from the issue text.