According to The Journal, it would seem that Microsoft's latest security updates aren't playing nice with VMWare viewer. The updates in question, KB2482017 and KB2467023, seem harmless enough but will break VMware's viewer application. There hasn't been any explanation as to how and why this has happened but luckily VMware has released a patch to resolve the situation.
VMware also recommends installing the patch before updating Windows 7 machines if the newest Microsoft security update hasn't been installed.
The challenge, however, arises in some companies that allow their staff to bring their own devices to work for use with company data (BYOD - Bring Your Own Device). By default, Windows will automatically download and install update patches, prompting the user to reboot on completion. In this case, a patch was issued fairly quickly by the vendor of the third party application. If a company is using a line of business application (LOB) that is subsequently broken by a windows patch, this can cause severe downtime in these scenarios.
Generally speaking, away from the BYOD scenario, it is becoming increasingly important that companies implement a proper patch management strategy and ensure that where possible WSUS is deployed to prevent these kind of issues. For home users, it is advisable that you wait a few days and keep an eye on sites like Neowin and the Neowin forums to make sure that no one has experienced issues with the patch prior to installing.