If you have a databounded DataGridView also the data source can be the reason for this problem.

In my case a get property inside the data source always throws an exception because it depends on other properties which were null at the moment of populating. I did not processed this exception (stupid, I know) but I saw a log message at the console which gives me the right info.

After preventing this exception the DataGridView was populated in a normal way.

Hope this helps...