Google Wiki:Unable to Process This Video

In Google Drive, a user may occasionally receive an error, stating Unable to process this video. This error indicates that the video file is corrupt or unreadable. This is often because Google Drive is unable to read the encoding or file format. This error was especially common when Google Drive was first released, but has since become more rare, as Google has put effort into supporting more file formats.

Solution
To fix this problem, it may be necessary to download your video from Google Drive, and convert it using a traditional video converter. Alternatively, you could try converting it online, by searching for an online video converter.

Converting the file will fix this error most of the time, but in case you continue to experience this issue after converting the file, it may be best to contact Google customer service about the problem.