Open source support can cause a lot of confusion. An accounting VAR whom I've known for 25 years explained that her company used a Microsoft open source app, an add-in to Solomon (now Microsoft Dynamics SL), for several clients. "It was the only way we could get Time Entry to work from a Macintosh," she said. "We dropped [the open source app] when the clients upgraded because we were forced to. Microsoft did not upgrade the product for the next version! Very sad situation; clients now had to pay for something they did not fully understand was free... messy.
Some of the people who responded to my query pooh-poohed the whole support issue because, they claim, most business-class open source apps have qualified consultants who can provide enterprise-level support. Cool. But how obvious will that be to the casual observer? Does your project web site have any list of "professionals who can help you put this WayCool technology to work"?
Politics plays a part, too. "My manager purchased the proprietary [app], and if we keep using the open source (what we like better), it may suggest that this purchase was not necessary," admitted one person. That points to the entire issue of "how to manage your boss," which is more a management topic. Few open source projects can address that issue directly, but if you're trying to gain corporate adoption, perhaps it's worth considering creating a wiki that helps your individual users "sell it" to the company. ("Make the boss look good" is always a good idea.)
Now that you've seen why people rejected your open source app, it's your turn: What made you dump an open source app you were using? What could that project have done differently?