This afternoon, I tried importing an existing project into Eclipse. Doing a Project > Clean usually clears up the R.java not found errors, but this time it didn’t work. I tried re-importing the project, copy-and-pasting it into a new workspace, restarting Eclipse, but the error is still there.
Just a quick note to self: If there is an error in the layout files, resolve that first then Clean.
I find it weird that no more specific error message is presented. Oh well.