settings trouble

Might be corrupted preferences ...

Open the Finder.

From the Finder menu bar click Go > Go to Folder

Then copy and paste the following:

~/Library/Preferences/com.apple.systempreferences.plist

Click Go then move com.apple.systempreferencs.plist file to the Trash.

Restart your Mac then check System Preferences.

Ok..

Back to copy / paste

~/Library/Caches/com.apple.systempreferences

Click Go then move the Cache.db file from the com.apple.systempreferences folder to the Trash.

Restart your Mac.

backup now. Then

- Install the 10.10.5 Combo update

Download OS X Yosemite 10.10.5 Combo Update

- Next if still probolem, boot to Recovery and repair the startup disk

OS X: About OS X Recovery - Apple Support

https://support.apple.com/en-us/HT201314

- If it is repairable reinstall the OSX

How to reinstall OS X on your Mac - Apple Support

https://support.apple.com/en-us/HT204904