Hi, this happened to me for the first time tonight.
Exporting a 5 minute track to FLAC format, 48k 16-bit. This would normally take about 30-60 seconds. At the moment it's on course to take about 40 minutes.
Now this is radically different from similar tracks I've worked on recently in that it uses quite a lot of plugins, and several of them are new to me.
So my main question really is whether the use of particular VSTs within a project is likely to have a major effect on the time taken for mixing down audio. I'm less bothered about tracking down a culprit initially.
It's hitting the CPU pretty hard during this (30%) although I notice Cakewalk is using very little RAM (400MB).