Some MKV video files only show a filetype icon rather than a thumbnail.
Switching to the details view, I can see that the Video Codec column for the problem files shows a blank entry.
The files play fine using the internal viewer.
Other file managers (Windows File Explorer, XYPlorer, OneCommander) all show / generate the thumbnails correctly.
Any suggestions I can try to fix this would be appreciated
Thanks
Opus gets video thumbnails from the Windows shell, so they should be identical to what you see in File Explorer for the same file. (Assuming a normal, local file. Cloud storage can complicate things.)
If you're seeing different results, open Preferences, then close all Opus folder windows/tabs, and clear the thumbnail cache via the button in Preferences / File Display Modes / Thumbnails / Performance.
It's also possible that something is blocking Opus from opening the file, which might explain the empty codec column. (Hard to say for sure without an example video that has the problem.)
I can confirm these are local files.
I've cleared the thumbnail cache (both in Opus and Win11 / Storage)
Windows has regenerated the thumbnails in File Explorer but Opus is still showing icons. The Dimensions / Duration / Codec columns all remain blank. (right clicking on a video and choosing Properties / Details does show Frame Width and Frame Height correctly)
I also tried changing my default viewer from MPC-BE to PotPlayer in case that made any difference to the way thumbnails are created.
I will also try installing Opus onto a backup machine that has a fresh Windows install to see if the problem exists there as well