MacOS Disk Images not unmounted

[biTshifT]

Checks

• I have searched github.com/aws/amazon-q-developer-cli/issues and there are no duplicates of my issue
• I have run q doctor in the affected terminal session
• I have run q restart and replicated the issue again

Operating system

macOS 26.5.2 (25F84)

Expected behaviour

When updating kiro-cli mounts a dmg file to install the update. On completion it should unmount this volume to ensure that dangling volumes don't consume disk space.

Actual behaviour

Kiro-cli does not unmount the volume, instead leaving the dangling volume and creating a new one each time. Over time this consume GiB of disk space due to these dangling volumes that don't ever appear to be cleaned up. The user has to manually unmount them (e.g. sudo diskutil unmount force) in order to clean them up.

Steps to reproduce

On a MacOS system that has had multiple kiro-cli updates run df -hal. On the affected systems there were multiple Kiro CLI volumes of the form:

/dev/disk7s1     1.3Gi   1.3Gi   2.7Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 1
/dev/disk8s1     1.3Gi   1.3Gi   2.6Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 2
/dev/disk9s1     1.3Gi   1.3Gi   2.7Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 3
/dev/disk10s1    1.3Gi   1.3Gi   2.6Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 4
/dev/disk11s1    1.3Gi   1.3Gi   2.6Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 5
/dev/disk12s1    1.3Gi   1.3Gi   2.6Mi   100%     101  4.3G    0%   /Volumes/Kiro CLI 6

Environment

<This will be visible to anyone. Do not include personal or sensitive information>

[q-details]
version = "2.16.0"
hash = "ac4bc3b1417d7cec0c95266cd23b5e7feb8aa3f6"
date = "2026-07-30T22:38:17.601521Z (3d ago)"
variant = "full"

[system-info]
os = "macOS 26.5.2 (25F84)"
chip = "Apple M1 Pro"
total-cores = 10
memory = "32.00 GB"

[environment]
cwd = "/Users/USER/workspaces/EC2ReleaseVelocityAICapabilities/src/EC2ReleaseVelocityProgram"
cli-path = "/Users/USER/workspaces/EC2ReleaseVelocityAICapabilities/src/EC2ReleaseVelocityProgram"
os = "Mac"
shell-path = "/bin/zsh"
shell-version = "5.9"
terminal = "iTerm 2"
install-method = "unknown"

[env-vars]
PATH = "/Users/USER/.local/state/fnm_multishells/3700_1784712440745/bin:/Users/USER/.bun/bin:/Users/USER/.aim/mcp-servers:/Users/USER/.pyenv/shims:/usr/local/opt/mysql@5.7/bin:/Users/USER/.rbenv/shims:/usr/local/sbin:/Users/USER/.toolbox/bin:/Users/USER/bin:/usr/local/bin:/Users/USER/node_modules/.bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/pkg/env/global/bin:/Library/Apple/usr/bin:/usr/local/go/bin:/Users/USER/.cargo/bin:/Applications/iTerm.app/Contents/Resources/utilities:/Users/USER/.local/bin:/Users/USER/.local/bin:/Users/USER/Library/Application Support/Coursier/bin:/Users/USER/.cargo/bin"
QTERM_SESSION_ID = "3b7b6f69962c40cca712476e539c545e"
Q_SET_PARENT_CHECK = "1"
Q_TERM = "2.13.0"
SHELL = "/bin/zsh"
TERM = "xterm-256color"
__CFBundleIdentifier = "com.googlecode.iterm2"