Exported 4K file isn't playable

[Zach5C84]

Using Premiere Pro CS6, exporting H264 mp4 file that is 30fps 3840x2160, which is the same format as the source video clips.

When I export a file containing multiple combined clips, the file won't play on any media player program. With the file open in VLC and checking the codecs under current media info, it's blank.

When I export a file containing just one of the clips, the file plays just fine and the codecs show as they should in VLC.

Also while working in the project file, I get an error when I try doing Sequence>Render Effects or Render Work Area.

Do I need to perform a certain action before exporting? I don't know if I'm doing something wrong or if Premiere Pro is just being fussy.

[Jeff Bugbee]

First: I'm not sure CS6 supports 4K. 

Second: If it does (or you can simply try this), take a look at this table: https://en.wikipedia.org/wiki/Advanced_Video_Coding#Levels

Make sure your H.264 export settings are at least a level of 5.1. Maximum bitrate for 4k is theoretically 240mb/s, but obviously try something far lower first. 

See if that gets you anywhere.

[Zach5C84]

I'm able to export a single 4K clip from the project and it plays in 4K just fine. This problem is when I try exporting a project that contains 2+ clips.

Profile is High

Level is 5.1

Bitrate encoding is VBR, 2 pass

Originally tried target bitrate of 80mbps and max of 100mbps, then also tried 35/45.