Problem when exporting to Vimeo I get message "The share operation has failed. Quicktime error: -50" The file only gets to 8% before this happens any idea how to fix I have a movie deadline to meet!

Question

Hi all,
Finished editing a short movie.
Then went to share on vimeo but got this message - see also screenshot when I tried to export to desktop.
Problem when exporting to Vimeo I get message "The share operation has failed. Quicktime error: -50" The file only gets to 8%.
Have tried deleting my render files for the project and also another fix mentioned of deleting any black space files on the edit itself but neither work?
Just upgraded to OS Mavericks could this be causing it? If so how to downgrade?
thanks
Louis B

Answer 1

Thanks for your help both, I called Apple tech support and spoke to a really helpful chap called Andrea who helped me out. Now got my Master file sorted and am trying Vimeo upload again.
Just to clarify points for people out there with the same issue:
First steps
- Ensure background rendering is turned off in preferences
- Delete project and events render files
- If upgraded to Mavericks then go to FCPX in finder under applications hit buttons 'CMD' and 'I' together and tick the 'prevent App Nap' box.
Next Steps
I had already done all of this when Apple Tech spoke to me so we discussed the message 'Quicktime -50' and what it meant. It wasnt a purely generic error message but was not detailed enough to point to one specific issue. This problem had occurred in previous years (so Mavericks not wholly to blame) and patches were issued over the years by Apple to help resolve some of the problems.
The message essentially is indicating that there is a problem somewhere with the media in some way shape or form.
My export went to 8% then failed. Apple's answer was that the project settings were corrupted in some way.
So what they suggested (so simple I could kick myself) was to select all the media files by 'CMD + A' then copy them 'CMD + C' then create and open a new project timeline, and then paste in 'CMD + V'.
Then we tried export again this time to a master file with some settings detailed by Apple.
The difference now was it got to 40% then failed but due to a different reason 'error -1 frame 10124 error'
At last we get past the project issues and into the event media issues, it seems that when I loaded the compact flash last night, the iMac kept ejecting the reader so had to copy files over quickly and seems that some of the file clip I used although showed on the viewer, didn't seem to have loaded all the correct media, so selecting this clip frame 10124 on the viewer I found that it showed as red on the frame row which implied an issue. So I simply bladed it off and deleted it.
Then I reran the export to Master file and it worked, though jumping from 40% to 100% complete was a shock to me!
Now am trying the export to Vimeo - hope this helps some of you out there. Worst case pick up the phone to Apple and speak to the Final Cut Pro guys they can help.
best wishes,
Louis B