I see an old thread has got no answers since October: http://forum.avast.com/index.php?topic=138146.msg1009428#msg1009428
Yup, creating a Rescue Disk dumped 1.5Gb into ‘My Documents’…
Those are NOT MY DOCUMENTS 
…I have moved them to a directory that doesn’t get File History backups. But I assume this download is why the first Rescue Disk creation took so long… Would be nice if Avast could find them the next time around…
…as always any help appreciated