In "enterprise" environments, I've observed a strong prejudice towards proprietary software. Even in large business that use Java, it is unusual to find MySQL or PostgreSQL, and WebSphere and WebLogic are strongly preferred over JBoss or Tomcat.
This is very understandable. While many developers prefer Tomcat or Postgres to WebSphere or Oracle DB, they are not the ones that make the final decisions in these matters. Whoever does make the decision regarding which DBs and application servers will be used in production will find that the licence fees seem quite small compared to being fired for choosing the free software that caused something really, really, bad to happen.
I'm not asking the question of whether Postgres is as good as Oracle. That's not the point. Oracle doesn't get chosen over Postgres after a careful considerations of features and benchmarks. Postgres doesn't enter the conversation, because free software isn't trusted in certain places.
I'm curious if this lack of trust came about in response to any specific events. So my question is this: Are there any documented cases of business calamities (failures, significant loss of revenue, significant loss of corporate data, etc.) that were shown to be the result of deficiencies in open-source software?
Clarification: If you have experience with enterprise level companies that fully embrace OSS, that have to prejudice in the matter but make choices based on the needs of the particular situation, then Good for you! Your experience doesn't change the fact that other enterprise companies have a very different attitude, and my question is valid even if these companies are in the minority.