This error does not happen often but I need to give a return to the user.
In this case, when the user attempted to change the text (without using copy / paste) from Content below, he received the message:
system clipboard data unavailable.
The change could not be made even by finalizing and restarting the Integrity Client.
The only way was to boot the user's computer.
Try to select any text e.g. the one from the error message and add that to the clipboard via CTRL+C.
This should resolve the issue.
Just to add to this:
What version of Integrity did you see this on?
I know Integrity support has seen the rare occurrence of this issue, but they have not been able to get reliable info or logs, when this issue occurs, so you may want to log a Support case, if this occurs again. There is an internal article for this issue (article # 293439 - not customer visible yet because of lack of details).
I also ask what version of Integrity you saw this on, because I've only seen cases of this on older 10.8 and 10.9 versions that I know of, so it would be good to confirm if it's happened on newer versions of Integrity. It's possible this could be a Java bug too, which has changed with subsequent Integrity releases.