Xcode 10: what is in 'Library/Developer/Xcode/UserData/IB Support/Simulator Devices'?

Question

I noticed that this directory: /Users/$USER/Library/Developer/Xcode/UserData/IB Support/Simulator Devices

contains some rather large directories on my Mac:

$ du -d1 -h | sort -h
...
1.7G    ./A7F495BF-B286-4A8B-83A7-7E3D32A237AE
2.4G    ./E9F53010-C7A9-469D-8859-D482D6D334FC
5.9G    ./E85370F1-3126-4679-AA61-35DCAA6B7871
9.8G    ./56FB0674-0DA8-41BA-BA0D-0398CF2139A1
 22G    ./9F55C8ED-15A2-4FF7-8052-BA4464B290F9
 32G    ./3CA6DF23-014A-4939-9B5F-9039655B8D03

Digging a little deeper, 3CA6DF23-014A-4939-9B5F-9039655B8D03/data/tmp contains a lot of *.uicatalog files.

These UUIDs do not show up when I run xcrun simctl list.

Does anyone know what creates these files, and if it's safe to delete them?

Answer 1

Xcode creates those files after each build. They are unused, so you can delete them. If it is a server, you can periodically delete them:

Create a file with the library path:

sudo vim /etc/periodic.conf.local

In it, write:

daily_clean_tmps_dirs="/tmp /Users/bamboo/Library/Developer/Xcode/UserData/"

Run to make sure files are deleted every 3 days:

du -sh /Users/bamboo/Library/Developer/Xcode/UserData/IB\ Support/
sudo periodic daily