Sometimes I have lags when I play the unrendern video in camtasia. I dont know if this is normal but I accepted it because the rendered videos where ok. But in the last three videos, the same lags occured in the rendered videos. Why is this?
I recently called support because I was experiencing lags in my Camtasia project. I could close the project and reopen it as suggested by ExpertNovice, but this workaround never lasted long. I found I was closing and reopening projects several times an hour!
Apparently, there are video and audio limitations for files imported into Camtasia. The support person sent me this very handy link which recommends pre-processing with suggested freeware. The video explains exactly how to configure settings in the pre-processing freeware, Handbrake. This solution worked for me!