I'm in view that it's a leftover from a failed /write, /writeini, write to logfile, because it appears after i exit mIRC sometimes.
It is probably not due to a failed write - in any situation where mIRC fails to write to a temporary file, it deletes it without affecting the existing files. The only situation I can think of where the temporary file would be left behind is if it has been locked by another application, such as anti-virus software, preventing mIRC from renaming/deleting it. In such a situation, there is nothing mIRC can do, other than freezing indefinitely and repeatedly trying to rename/delete the file in the hope that it might become available at some point, which is not practical unfortunately.
