> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mobster.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# No space left on device

> Your Mac's disk is full, so Xcode couldn't write Mobster's helper. Free up space and build again.

You see this: `xcodebuild` prints `error: unable to open output file ... 'No space left on device'` while it compiles the helper.

## Why it happens

The build writes to Mobster's `wda-build` folder in `~/Library/Application Support/app.mobster.desktop/`. Xcode stops when the disk has no room.

## Fix

1. Free up space on your Mac.
2. Build again from Mobster for Mac.

## Check it worked

`mobster sim doctor` prints a `Free space` line with the room left.

Checked 26 Oct 2026 against Mobster 0.4.0. Back to [Troubleshooting](https://docs.mobster.dev/troubleshooting.md#iphone).


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