I made a video playlist via drag and drop and happened to see the play length of the list before saving the list, and had 6.7 billion hours 700,000 years of video from just 106, ~45 minute videos.

• Edited by ArkavianX Wednesday, April 15, 2015 1:49 AM

this issue maybe can be occur because unsupported video format

did you test to play all those video before safe it, I suggest try perform windows update and installed latest codec

https://support.microsoft.com/en-us/kb/2395168/

• Edited by britishdhez Wednesday, April 15, 2015 4:01 AM
• Proposed as answer by Roger LuMicrosoft contingent staff, Moderator 1 hour 37 minutes ago