Open Radar

 
Summary:
OS X user configuration profile goes missing after booting from a previous version of OS X, OS X Snow Leopard (10.6.8), from an external hard-drive. 

It is probably related to bugs/issues regarding to the implementation of CoreStorage (and FileVault 2?).

Steps to Reproduce:
1. Make sure the Mac is running OS X Yosemite and has CoreStorage turned on. FileVault 2 can be off.
2. Turn off Mac.
3. Boot up Mac while holding Option key, and choose to boot from Snow Leopard partition (located on an external hard drive).
4. Use it for a while, then shut down Mac.
5. Turn on Mac while holding Option key.
6. Choose to boot from the native Yosemite partition.

Expected Results:
1. Computer operates normally under OS X Yosemite. No files, applications or configurations are wiped or removed.

Actual Results:
1. Computer opens Setup Assistant, showing the same landing experience for reinstalling OS X, asking for iCloud credentials (but does not ask to create new user account).
2. It seems like the Mac discarded all data that can be potentially encrypted by FileVault. The Mac seems "fresh". No document is left. All 3rd party applications disappear. Dock and Launchpad settings are reset. Spotlight reindexes and all preferences are gone.

Version:
Early 2011 MacBook Pro,
Mac OS X Snow Leopard 10.6.8,
OS X Yosemite 10.10.3.

Configuration:
Early 2011 MacBook Pro,
Mac OS X Snow Leopard 10.6.8,
OS X Yosemite 10.10.3.