Smartlab Software had an interesting problem occur: a client was having MySQL connection problems only on Windows 8 or 8.1. XP, Vista, and Windows 7 were fine. The problem manifested itself by showing the HTML part of a dropdown box.
I verified that Windows 7 worked but in my case, Windows 8.1 also worked. One piece of the puzzle.
After poking around the Internet, a thought was the IP4 vs IP6 connection problem. This affected Windows 7 and 8 so it was unlikely.
The client booted up in safe mode and didn’t have a connection problem. In safe mode, the antivirus was disabled. It turns out the Windows 8.1 computers were brand new and came with a trial version of Kapersky antivirus. After uninstalling it and replacing it with another antivirus program, everything is back to normal.