I rarely use the trimmer. Mine has always been unchecked.Not sure how to interpret the potential problem.

Some background from the help file:

"If the selected file type cannot save markers internally, Vegas Pro will save the metadata to an external file with an .sfl extension (using the same base name as your media file)."

As examples, Sony AVC markers and regions get saved internally in the MP4 file. XAVC-I markers and regions get saved externally in a .sfl sidecar file.

TEST METHOD

1. Make sure "Preferences > General > "Automatically save trimmer markers and regions with media file" is unchecked.
2. Open Windows (File) Explorer at the folder where a media file is located (not ProRes, HEVC or XAVC-S, which have issues).
3. Note "Date modified" time for the media file, and whether a .sfl file (with the same base name) exists for it.
4. Open media file in the Vegas trimmer.
5. Add some markers and regions (hit "M" or "R" to make it quick).
6. Dismiss the trimmer window with the "X" at the top right.
7. See the "Modified" time of your media file change, or the appearance of a .sfl file for it. They shouldn't but for me they do.
8. Open a new project.
9. Open the media file in the trimmer or on the timeline.
10. See the markers and regions appear on the file. They shouldn't but for me they do.

Vegas 13-453 on Windows 7 Pro

.mp4 (Rendered)= yes.

If I delete them from the file in the Trimmer and save the project, they still return. If I open the file in a new project they are still there.

.MOV Canon files = no

.MP4 from Sony RX10iii = no

.MP4 from Canon T6i = no

Thanks John. I'll test some more formats.

I tested a load of different formats and basically, on my system, VP14 is just ignoring the "Automatically save trimmer markers and regions with media file" preference being unchecked and saving them anyway:

IMO quite dangerous in the case of those MP4 formats at the top of the list. I don't want any software putting metadata into my original files unless I tell it to.

Support request: [Ticket#2017051217000736]

I'd prefer that markers be saved in SFL files for all formats. I also don't like when they are saved in media files.

I'd prefer that markers be saved in SFL files for all formats. I also don't like when they are saved in media files.

I fully agree.

I'd prefer that markers be saved in SFL files for all formats. I also don't like when they are saved in media files.

I'd certainly like that as an option.