Boot stops at Spotlight icon

My company has three Mac Pros purchased last fall. When I first set them up, one of them had a problem where the boot process would stop. It always occurred right after the Spotlight icon appeared in the menu bar. I eventually created a second account for the computer and the problem went away.

Today, a second Mac Pro had the same process. The Spotlight icon is the first to appear on the menu bar and the boot process stops. My solution was the same. Boot into safe mode and create a second account.

Any ideas?