I have XP and I get this message sometimes too. I don't think it is OS related. The message says that it is rebuilding the runtime menu tree which might take several minutes, but actually it is very fast. Maybe it thinks that the state of runtime has changed because the user manually added or deleted some files. (I didn't though.) It only started to appear quite recently. Casette: maybe we should post in the CP support forum. I will try to make a note of the exact message next time it appears.