I also had some data corruption on one drive where there was an avast sandbox folder.
What is that? I mean, aren't you able to save a file in disk?
two things, I didn't mention it but I had to re-install Windows completely yesterday night. What happened is I rebooted when RAM use was too high, than automatically, CHKDSK showed the message at boot time about inconsistencies on a drive, and I saw it was restoring corrupted files. At the same time, while running Windows, it was getting more and more difficult to copy or delete files, dialog boxes were hanging >>> "discovering items" etc...I tried to create a new account >>> when attempting to login with the new account I got this message: "the user profile service failed the logon. User profile cannot be loaded. Happened two or three times. There was an unknown profile listed in advanced settings/performance...I deleted that, logged out, logged back in with my regular account and something bad happened

my EFS certificate got deleted and replaced by a newly generated one. No big deal (although I have no idea how this can happen) I got a backup of it, re-imported it, made sure that all encrypted data were using it, and decided to re-install Windows.
Memory leak came back today, but no corruption so far...well hopefully. I did a check disk on C: and it corrected a few things, unindexed stuff and free space to recover, no big deal I think . My fear is that the sandbox could corrupt partitions...