Metadata Editor (MDE) does not launch

Symptom:

When I try to launch the Metadata Editor (MDE) nothing happens.

Resolution:

Try these steps:

1. If possible disable your anti-virus and try launching the MDE.
2. If your MDE launches then you will need to whitelist the folder that the MDE is running from (see Notes).
3. If it still does not launch, attempt to re-install the MDE.
4. If re-installing did not work, further investigation will be required. Please contact [e-mail]. 

Root Cause:

This problem is likely caused by one of two problems. Either your anti-virus is blocking the MDE from launching or the MDE installation has been corrupted.

Notes:

The best path to whitelist is C:\Users\*\AppData\Local\Apps\2.0\*\*\*\ 
The wildcard entries are necessary as those folders can vary on a per user basis.