If I filed bankruptcy can a bank still change the locks on my house and keep me out?

You have a number of problems that cannot be fully assessed through your question. The problem is that there was apparently no delivery to either the Sheriff or the Bank of the proof of your filing bankruptcy.  This is something that needs to be addressed with your attorney.  It may be that the Court sent out notice or counsel did.  Should that have occurred, there is an initial question of when and to whom.  As a result, there may be a claim for violation of the automatic stay. Another problem is the May 9th eviction date.  Due to changes in bankruptcy law in 2005, provisions were added regarding the need for posting of bonds in eviction matters to be stayed by bankruptcy filings.  It may be that your situation feel within these provisions.  As a consequence, the eviction may not have been a violation of the stay.  In short, the right to evict you may have existed when the eviction actually occurred despite the filed bankruptcy.  Again, this is something to address with counsel. In the event of improper eviction, an action could lie with the Bankruptcy Court.  You question did not indicate you had an attorney.  If so, you should address these matters with your attorney.  Should you have filed it without counsel, you can look to speak with an attorney that is experienced in bankruptcy and stay enforcement/violations.  An internet search or a call to your county bar association should provide you with the names of such persons in your area.