There could be a number of reasons that the file is not uploading:

1. Check that you can open the file and it not corrupt.  If it is you will need to either save the master again or create a new file.

2. Fresh the cache on your PC by pressing command R and then try again.  

This could be an issue local to your PC and by clearing the cache should resolve the problem.  


If however you have tried both suggestions and are still having issues then please contact our Support Helpdesk so we can check it for you.