Problem
As of May, 2014, the current version of WebEx client (Older versions of the WebEx Meeting Center program may not support Windows 8 & 8.1 ) does not fully support file sharing for along with some MS Office 2010/2013 file types (e.g. MS Word, Excel, PDF and PowerPoint)
Solution
The work around is to use "Share Application" instead of "Share File". The WebEx Support team will inform us when the issue is resolved.current version of WebEx client works. Please uninstall and reinstall the application
or
You can use Application Sharing instead of File Sharing
Notes:
From WebEx Support, May 28, 2014 (Byron) - Re: Windows 8 & 8.1 - file sharing
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