Unknown DB Error When Trying to Disable the Automatic Wildcard Option
I started experiencing this also, although I was trying to enable the auto wildcard option, which I had previously turned off.

I think it's a bug, but did have success updating it directly in the database as a workaround. In the civicrm_setting table there's a value called includeWildCardinVlaue. s:1:"1" means "yes" it's on, s:1:"0" means "no" it's off.

I'm running Civi 4.7.3 in Wordpress 4.4.2 on civihosting.com.

Looks like it might be happening to Drupal users, too. Why can&#39;t I save search preferences? Specifically &#39;Autocomplete Results&#39;