# Fixed: Unreal Engine 5.4.4 install failed around 70%, IS-IN-FC02, Xcode not detected, then crash on MacBook Air M1 / macOS Sequoia

**URL:** <https://forums.unrealengine.com/t/fixed-unreal-engine-5-4-4-install-failed-around-70-is-in-fc02-xcode-not-detected-then-crash-on-macbook-air-m1-macos-sequoia/2729988>\
**Category:** Getting Started & Setup\
**Tags:** unreal-engine, troubleshooting\
**Created:** [June 19, 2026, 7:39pm UTC](https://forums.unrealengine.com/t/fixed-unreal-engine-5-4-4-install-failed-around-70-is-in-fc02-xcode-not-detected-then-crash-on-macbook-air-m1-macos-sequoia/2729988 "2026-06-19T19:39:29Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Hashiba](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/hashiba/32/1184100_2.png) [@Hashiba](https://forums.unrealengine.com/u/Hashiba)\
**Post date:** [June 19, 2026, 7:39pm UTC](https://forums.unrealengine.com/t/fixed-unreal-engine-5-4-4-install-failed-around-70-is-in-fc02-xcode-not-detected-then-crash-on-macbook-air-m1-macos-sequoia/2729988/1 "2026-06-19T19:39:29Z")

</div>

## Fixed: Unreal Engine 5.4.4 install failed around 70%, Xcode not detected, then crash on MacBook Air M1 / macOS Sequoia

I was finally able to install and launch **Unreal Engine 5.4.4** on my **MacBook Air M1 running macOS Sequoia** after running into a few different problems.

I’m posting the full sequence because the error messages were a bit misleading. If I had to install Unreal again on this machine, this is what I would check/do first. This will probably work for most versions, I’ve used 5.4.4 on my air because 5.7 might be too demanding for my prototype.

* * *

 ![Screenshot 2026-06-19 at 2.45.19 PM](https://d3kjluh73b9h9o.cloudfront.net/original/4X/a/0/d/a0d6e2aa163b34d5c960694d774abc43e964c694.png)

1. If the install fails around 70% with “file corruption”

My install was failing at around **71%** with:

```bash
Install Failed
A file corruption has occurred. Please try again.
Error Code: IS-IN-FC02

```

What fixed it for me was launching the Epic Games Launcher with a higher open-file limit.

First, close the Epic Games Launcher completely.

Then open Terminal and run:

```bash
sudo sysctl -w kern.maxfiles=131072 kern.maxfilesperproc=65536

```

Then launch Epic Games Launcher from the same Terminal session with:

```bash
ulimit -S -n 65536 && open -a "Epic Games Launcher"

```

After that, I went back to the Unreal Engine install in the Epic Games Launcher and clicked **Resume**.

This allowed the installation to continue successfully.

My guess is that the installer was hitting macOS file descriptor limits while unpacking/verifying a very large number of files, and Epic reported it as “file corruption,” even though the files themselves may not have been the real problem.

* * *

## 2. If Unreal says “Xcode Not Found” even though Xcode is installed

 ![Screenshot 2026-06-19 at 2.53.40 PM](https://d3kjluh73b9h9o.cloudfront.net/original/4X/4/c/4/4c4cd821353f2fd769c9a60b9797fd3bf6711adf.jpeg)

After the install, Unreal failed to launch and showed:

```bash
Xcode Not Found

Unreal Engine requires Xcode to compile shaders for Metal.

```

But I already had both Xcode and the Command Line Tools installed.

When I checked:

```bash
xcode-select -p

```

It returned:

```bash
/Library/Developer/CommandLineTools

```

So macOS was pointing developer tools to the standalone Command Line Tools folder instead of the full Xcode app.

Trying this also failed:

```bash
sudo xcodebuild -license

```

with:

```bash
xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

```

The fix was:

```bash
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

```

Then I verified/accepted the Xcode license:

```bash
sudo xcodebuild -license

```

After that, Unreal detected Xcode correctly.

* * *

## 3. If Unreal crashes with “Bad CPU type in executable”

After fixing Xcode, Unreal started launching but then crashed with:

```bash
Fatal error: FMacPlatformProcess::CreateProc: posix_spawn() failed (86, Bad CPU type in executable)

```

The important part is:

```bash
Bad CPU type in executable

```

Since this is an Apple Silicon Mac, that suggested something inside Unreal or one of its helper tools was trying to run an Intel/x86\_64 executable, but Rosetta was not installed.

The fix was:

```bash
softwareupdate --install-rosetta --agree-to-license

```

After installing Rosetta, Unreal Engine 5.4.4 launched successfully.

* * *

## Final sequence I would use next time

So if I had to install Unreal Engine again on an Apple Silicon Mac, I would do this:

```bash
# Make sure macOS developer tools point to full Xcode, not only Command Line Tools
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

# Accept the Xcode license
sudo xcodebuild -license

# Install Rosetta, needed by some Intel helper binaries
softwareupdate --install-rosetta --agree-to-license

# Optional but useful if Epic install fails around 70% with "file corruption"
sudo sysctl -w kern.maxfiles=131072 kern.maxfilesperproc=65536
ulimit -S -n 65536 && open -a "Epic Games Launcher"

```

Then resume the Unreal Engine installation from the Epic Games Launcher.

This fixed the install and launch problems for me on:

```bash
MacBook Air M1 8GB RAM
macOS Sequoia 15.7.4
Unreal Engine 5.4.4

```

Hope this helps someone else who runs into the same combination of issues. This will probably work on newer versions too.