WMV is a process-intensive format (all of their CODEC's), so it could be that your computer is just not up to that task.
The answers to the questions posed in Jim's link, will likely tell the story.
Please let us know a bit more,
Hi there, sorry for the lack of info!
I have PP CS6
I have just recieved permission from my IT dept. to download the updates for my Adobe package and am updating as we speak
Operating system = Windows 7 service pack 1 64 bit
footage type (H264) mp4
error message when encoding (Unknown error)
Was exporting to wmv
has worked before, was using custome settings redcing the average video bit rate to make the video smaller for upload
no i do not have any third-party effects or codecs installed
Intel(R) Core(TM) i7-3930K CPU @ 3.2GHz 3.2Ghz
NIVIDIA Quadro 4000
I have no idea if i am using "Mercury Playback Engine GPU acceleration"
Only happens with final output
Unfortunatly I am unable to post a video up of my issues as the downloads have not been granted by the IT department
thank you all for your fast response!!! It is very helpful indeed