My HD suddenly got full. After running WinDirStat I've found that C:\Windows\AppCompat\Appraiser\Telemetry contains more than 300GB data (from a total of 500GB on my laptop). Before noticing this I've deleted lots of files and released almost 100GB. Then, 3 days later, there was another message saying my HD was almost full again.
I'm running Windows 8.1
*I'm not a native English speaker, so I'm sorry for any language mistakes =/