We do monitor User Voice; we share your disappointment that we don’t have a reproducible case, for this issue.
If you can reliably reproduce the ‘low level exception’ problem, on your system, please contact Support and provide them with any files and source media required for that repro case, as well as (important!) step-by-step instructions on how you can reproduce the issue.
We’re eager to pursue the issue further.
An error occurred while saving the commentZheng Wang commented
I've been having this problem with older projects. Reliably, it's ALWAYS when there is an item on the timeline made with the old titler. If I delete those old titles from the timeline and restart Premiere, everything is fine.