More than 2600 video files in a folder

Directory Opus 12.19 and 12.19.4 react sporadically when there are more than 2600 .MP4 files in a folder. To reproduce, just turn on the viewer pane and select a different video. DO may behave normally, or more frequently will just halt for several seconds, or sometimes refuse to quit (the top-right "X").

I moved half the files to another folder, now everything seems normal.
Windows 10, Intel core 7, 16GB RAM.

FWIW, File Explorer and Xyplorer seem to work normally in the 2600 file folder.

Which columns are visible in the file display? Is there a spinning circle on the right of the location bar while this is happening?

I suspect Opus is reading metadata about the videos (or generating thumbnails, if in a mode which shows them), and that in turn is either slowing the disk down or triggering a conflict with one of the video codec/splitter which might be used for both metadata and playback in the viewer pane. (Codecs/splitters are often unstable, depending on where they came from and which version etc. they are.)

You can stop that from happening by avoiding any columns which cause the metadata to be extracted. (As well as the obvious columns in the video category, there's also the Description column. The status bar can also play a part, if you have duration information added to it.)

If doing the same test in File Explorer works, that surprises me since video playback has been completely broken in File Explorer's preview pane for a year or more, after Microsoft broke it in one of the Windows 10 updates and hasn't bothered fixing it since.

OK, "broke" is normal in File Explorer. I don't use it much.

Columns are Name, Status, Size, Modified, Label.

I'll check the Codecs, but Xyplorer works fine and as far as I know, uses the same codecs.

Do you have any labels defined that use metadata to color-code files?

Yes, many of the files are color-coded via Labels
When problem occurs, sometimes there's a spinner, sometimes just hangs. Top of the viewer pane says "loading". Turn off the viewer pane, and there's a spinner for at least 3 minutes. Click exit usually works, but sometimes I have to use Task Manager to get it to quit.

Color-coding won't necessarily be a problem, unless it's being done by a filter which looks at video metadata (e.g. duration, width, height, codec, etc.).

Try disabling the Movie plugin (Preferences / Viewer / Plugins) so videos always fall through to the Windows Media Player ActiveX control instead. That may solve things. (The Movie plugin doesn't work great with Windows 10, and is something we plan to replace in the future. But WMP generally works well. You may already be using WMP for playback, but if the Movie plugin is enabled it will try first and might get stuck, or slow things down at least.)

I'm just manually selecting whichever color is appropriate for the video type.
Disabling the Movie plugin did no good.

By the way, how can I set the width of the Name column, or get it to remember my last setting? I cannot find it in the Preferences...