When viewing the Flash video streaming content in Firefox 2 (FF2) and Firefox 3 (FF3) on video hosting sites, such as YouTube, MetaCafe, DailyMotion, ToDuo, YouKo, Vimeo, 56.com, Veoh, Revver, imeed, iFilm, GoFish and many more, or on web pages that embed code from these video sharing sites, the streaming video is not playing, or stop playing after one or two or three seconds.

The Flash video not playing error, or stops playback after few seconds problem happens despite the media buffering is running fine on the video seek bar. If viewer move forward or backward the video, it will play for around 2 seconds again, and stop again. And when using Internet Explorer, the YouTube video and other Flash video is loading and playing fine without problem. The symptom looks to confine with Firefox browser, both version 2 and 3.

Adobe Flash Player seems to have many problems, other been no sound when playing back the Flash video on YouTube or similar sites. To fix the FLV video not playing or just plays for 2 or 3 seconds error, which may be caused by corrupted Adobe Shockwave Flash Player plugin, try the following resolutions.

Solution 1: Copy NPSWF32.dll to Mozilla Firefox Plugins Folder

The Flash video playback terminated after few seconds issue may be caused by DLL file for Flash Player is located at invalid location. Copy and paste the NPSWF32.dll from C:\Windows\System32\Macromed\Flash folder (32-bit Windows) or C:\Windows\SysWOW64\Macromed\Flash folder (64-bit Windows) into C:\Program Files\Mozilla Firefox\plugins folder (32-bit Windows) or C:\Program Files (x86)\Mozilla Firefox\plugins for (64-bit Windows). Then restart Firefox browser.

Solution 2: Uninstall Old Version and Install Latest Version of Flash Player

Download the corresponding version of Adobe Flash Player uninstaller, listed on Adobe Technote:

Close all Mozilla Firefox web browser windows, and then run the Flash uninstaller downloaded from link above. After Flash Player uninstalled, download the latest version of Adobe Flash Player for Firefox, Mozilla, Netscape, Opera browser. Reinstall the Flash Player will likely to fix the YouTube Flash video not playing more than 3 seconds problem.

Solution 3: Install Adobe Flash Player 10

Exit from all Mozilla Firefox browser windows. Uninstall existing installed copy of Adobe Flash Player (most likely version 9 or earlier) using Uninstaller listed above. Download and install the Adobe Flash Player 10, which currently in beta phase, from Adobe Lab. The latest Flash Player 10 should fix all video playback on any sites error.

Solution 4: Start New Session of Firefox Browser

The FLV streaming video clip playback issue on YouTube, MetaCafe and other video sites may also happen due to too many tabs and/or windows of Firefox been opened. The exact cause is unknown, but potentially too many instances of Flash objects (not only your favorite movies or TV episodes use Flash for playback, some other elements or components on web pages, such as ads banner may be using Flash too) may mess up or corrupt the Flash plugin.

To fix this issue, close some or all the tabs opened, and then restart the Firefox browser. The video playback stops right after starting, not even before finishing problem should be resolved.