I'm analyzing an obfuscated binary. IDA did a pretty good job of doing the initial auto-analysis. Later, I went through and marked some sections as undefined, or code, etc. Now IDA can't re-create a section as a function. It complains about
The function has undefined instruction/data at the specified address.
I think this is because it has remembered where I've marked thing as undefined or data or code. And those marks are confusing the auto analyzer.