Introduction
Shortly after the release of the Microsoft Office July Public Update, we received notification of a potential issue that affects a subset of Microsoft Office 2013 and Office 365 Click-to-Run users. In some cases, these users cannot start Office products after the July 2014 Office updates are installed.
We have corrected this problem. On July 24, 2014, we started a phased rollout of updated build 15.0.4631.1004. A growing number of users will start to receive this fix during this gradual rollout. After the update is made available, users who want to apply the update immediately can do this manually. To obtain the latest Office build, click File, click Office Account, click Update Option, and then click Update Now on the options list.
Resolution
Users who experience persistent problems when they try to start Office applications can run an available Fix it to uninstall the affected applications and install the latest bits. The Fix it is provided in the following Microsoft Knowledge Base article:
2739501 How to uninstall Office 2013 or Office 365
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.