I have created several databases that we use it the office. They are kept on a server. Recently, we started getting a security warning window everytime we open Access. It asks DO YOU WANT TO OPEN THIS FILE? and points out that the publisher is UNKNOWN PUBLISHER. If you click yes, it opens normally. However, from about that same time, we realized that we are not able to open a second copy of any of the databases. If someone else has a database open and I try to open it also, I do not get any error message, but it just ignores the opening click. I do not know if theses two changes to the way Access is operating are connected or not. IT does not think they did anything that would have triggered this. I am wondering if it is a trust issue, either between the individual computers or between our server and ITs server. I created a small, clean one table, one record database and stored it on my C drive. It operated normally. Then I copied it into the database folder on our server and got the new behavior.