I left my PC on to do a 2-pass Pseudorandom Data erase of unused space on my HDD, and I got told it could not be completed. I would post the entire log, but it's pretty long.
Information:
Statistics:
Erased area = 503675 MB
Cluster tips = 306119 kB
Data written = 1007349 MB
Write time = 39893.65 s
Write speed = 25857 kB/s
Failures:
Error: Failed to remove a temporary directory from drive C:\, you may want to remove it manually to recover (possibly) lost disk space.
Failed: C:\Boot\BCD
Failed: C:\Boot\BCD.LOG
Failed: C:\Boot\cs-CZ\bootmgr.exe.mui
Failed: C:\Boot\da-DK\bootmgr.exe.mui
Failed: C:\Boot\de-DE\bootmgr.exe.mui
Failed: C:\Boot\el-GR\bootmgr.exe.mui
Failed: C:\Boot\en-US\bootmgr.exe.mui
Failed: C:\Boot\en-US\memtest.exe.mui
Failed: C:\Boot\es-ES\bootmgr.exe.mui
Failed: C:\Boot\fi-FI\bootmgr.exe.mui
Failed: C:\Boot\Fonts\chs_boot.ttf
Failed: C:\Boot\Fonts\cht_boot.ttf
Failed: C:\Boot\Fonts\jpn_boot.ttf
Failed: C:\Boot\Fonts\kor_boot.ttf
Failed: C:\Boot\Fonts\wgl4_boot.ttf
Failed: C:\Boot\fr-FR\bootmgr.exe.mui
Failed: C:\Boot\hu-HU\bootmgr.exe.mui
Failed: C:\Boot\it-IT\bootmgr.exe.mui
Failed: C:\Boot\ja-JP\bootmgr.exe.mui
Failed: C:\Boot\ko-KR\bootmgr.exe.mui
Failed: C:\Boot\memtest.exe
Failed: C:\Boot\nb-NO\bootmgr.exe.mui
Failed: C:\Boot\nl-NL\bootmgr.exe.mui
Failed: C:\Boot\pl-PL\bootmgr.exe.mui
Failed: C:\Boot\pt-BR\bootmgr.exe.mui
Failed: C:\Boot\pt-PT\bootmgr.exe.mui
Failed: C:\Boot\ru-RU\bootmgr.exe.mui
Failed: C:\Boot\sv-SE\bootmgr.exe.mui
Failed: C:\Boot\tr-TR\bootmgr.exe.mui
Failed: C:\Boot\zh-CN\bootmgr.exe.mui
Failed: C:\Boot\zh-HK\bootmgr.exe.mui
Failed: C:\Boot\zh-TW\bootmgr.exe.mui
Failed: C:\bootmgr
Failed: C:\config.sys (Protected File)
Failed: C:\Documents and Settings (Reparse point)
Failed: C:\hiberfil.sys
Failed: C:\pagefile.sys