Hello,
I'm not sure why, but for some reason I can no longer view any videos from the viewer. It just shows a black screen.
Please assist.
Thank you.
Do you know which viewer you are using?
- Under Preferences / Viewer / Plugins, is Movie enabled?
- If not, click ActiveX + Preview + Office + Web and please paste a screenshot of what is shown in there.
Under Preferences / Viewer / Plugins, is Movie enabled? Yes.
The video codecs/demuxers on your system, or related registry settings, may have changed. This guide may help fix that:
Alternatively, disabling the Movie plugin will allow the Windows Media Player ActiveX control to be used, which may work better.
Alternatively to that, keeping the Movie plugin disabled and configuring the ActiveX + Preview + Office + Web plugin to enable the Windows Media Player preview handler (which is different to the ActiveX control) is another option. (If you are on Windows 10, you'll want to be on the recent big Windows update for that, since Microsoft broke their own WMP preview handler for about a year preceding the last update, which finally fixed it).
Thank you! It's works (again)! 
I tried the method in the link provided, setting my file associations with Windows Media Player and it did not work for me. More so, all video formats seemed to have been broken at the same time, it seems the problem is with the Movie plugin being broken. (I also tried completely re-installing directory opus to get video working again, which didn't work)...
I think there needs to be some tool written to diagnose and fix the movie plugin registry settings, if that is what is actually causing this problem. I cannot write or fix this problem, and it's like I paid for a license for this program for a feature I thought would not just simply stop working after a few months. There needs to be a newer movie plugin written, if you cannot find any other way to fix this problem with the current version of the viewer movie plugin. Cause this is the most annoying issue with the program by far. I bought this program for organizing VIDEO FILES not to look at a BLACK SCREEN with audio but no video. I am just frustrated sorry.
I did try the Windows Media Player activex control but it autoplays the videos at full volume and is not customizable at all.
Use the WMP preview handler if you don't want autoplay.
Can't preview any videos.
I can hear the video, but no picture.
Other file previews (JPG, PDF, RAR, TXT, DOC) work fine.
Have you tried the suggestions above?
Reinstalled latest K-Lite Mega Codec Pack - no good.
Tried adding file formats here - no good.
Upd: MP3 files don't play too - just see MP3 icon in the preview area.
One more upd: Both MP3 and AVI file previews work fine in Total Commander 9.51.
So it's OK with my codecs, right ?
There's no Windows Media Player option under Preview Handlers, so my bet is that either your system is missing some of the WMP components (versions of Windows for some markets are like that, I think, although it's not that common) or something has damaged WMP's registry settings (the guide I linked above says how to fix them).
Once that is in the list, try turning it on to see if it can play videos.
Re Total Commander, it depends which codecs it uses. There are 32-bit and 64-bit ones, and also different types on top of that these days.