We have a Simatic PanelPC477B with WinCC Runtime 2007 running a user interface to a machine. We defined some users with passwords. These users worked fine for about 2 days, and then some of them stopped working (we did not change them, nor anyone else).

We had this problem before but we avoided the problem like this: if we had users: john, andrew and sam, we made john1, john2, john3, andrew1, andrew2, andrew3.... and if john wanted to log in, he would try first to log in with john1 and if it didn't work, he would log in with john2 or john3. The same with the other users. But it is improper and we would like to solve the problem, not avoid it.

What could be the cause of this? How can we solve the problem?

There is also one easy, but expensive solution. Upgrade to 2008, becasue you can set the number of invalid log attemps to 0 (and 0 being infinity).

Best regards