The software Timelapse uses to play / show videos is the one supplied by the Windows operating system. As Timelapse doesn’t do anything else with the video, the problem usually stems from your computer either missing its internal media player, or missing the video codec (compresseor/decompressor) needed to play the video. If the videos play within Timelapse on a different computer, then its almost certainly an issue with Windows (not Timelapse).

Solution 1. Making sure Microsoft’s internal Windows Media Player is installed

Try this solution first, as it is the most common remedy. Timelapse uses Microsoft’s internal Windows Media Player to play videos. If the Windows Media Player is not installed, then Timelapse cannot play the videos. To fix this, try installing or upgrading your installation of Windows Media player as described here and repeated below.

1. Click the Start button, type features, and then select Turn Windows features on or off. Alternately, type Turn Windows features on or off in the Windows 11 search bar.
2. Expand Media Features and see whether the Windows Media Player check box is selected.
3. If it is not selected, it means the Windows Media Player is not installed. To install it:
   1. Select the check box. Click OK and restart your computer.
4. If it selected, try to reinstall the latest version of Windows Media Player
   1. Clear the check box. Click OK and restart your computer, which will remove your current version of Windows Media Player.
   2. Repeat step one above to then install the latest version of Windows Media Player, where you check the check box, click OK and restart your computer.
5. Fire up Timelapse, and see if it now plays your video files.

Solution 2. Install missing Codecs

Codecs specific to your video are needed to display it properly. If the above solution doesn’t work, try installing various codecs as described below.

1. Similar to the above, there are other web sites that offer various codecs. One (untested) site is free-codecs.com . But be careful: check whether its a legit site.
2. Downloading the K-lite coded pack, which includes a variety of standard audio and video playback codecs. Restart your computer when done.
3. If none of the above works, this site seems informative: Install missing codecs in Windows

Solution 3. Other possibilities

1. Use an external video player. If you can run your video outside of Timelapse, make that player your Windows default video player. You can then use the Play External button in the Timelapse video player to view the video in that video player.
2. Use a different computer if it works on that.
3. Could it be a Driver issue? If nothing above works, another possibility is that your display driver is having issues. Maybe its an old machine, or you haven’t updated things for a long while. You can try to reinstalling your display driver.
   • Right click on Start button and click on Device Manager.
   • Select the Graphic driver from the list by extending Display adapters.
   • Right click on the Graphic driver and click on Update Driver Software.