I have been having this exact same problem, and it was with two different clients' files at their offices on their computers, so it wasn't just an isolated incident. My client and I just spent two hours on a support chat with an Intuit support agent, and the thing that finally seemed to solve the issue was going into the library and deleting all files that started with "com.intuit", moving them to the trash, and emptying the trash. After we did this, the problem seemed resolved, and to further test it, I opened a sample company (that had also previously malfunctioned when the agent wanted me to test it so that he could see it happen in their sample file), imported my credit card transactions, and it was fixed there as well.
