This is incomplete because I ended the task. On a subsequent test, the last file was write.exe even though I don't know if the code goes alphabetically or that's just how files are laid out on a fresh install.When Type Warning
2013-08-01 17:51:55,779 ERROR: Removing C:\Windows\servicing\TrustedInstaller.exe failed
2013-08-01 17:51:53,161 ERROR: Removing C:\Windows\regedit.exe failed
2013-08-01 17:51:52,772 ERROR: Removing C:\Windows\notepad.exe failed
2013-08-01 17:51:52,766 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\WsatConfig.exe failed
2013-08-01 17:51:52,736 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\vbc.exe failed
2013-08-01 17:51:52,651 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\SMSvcHost.exe failed
2013-08-01 17:51:52,648 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ServiceModelReg.exe failed
2013-08-01 17:51:52,642 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\RegSvcs.exe failed
2013-08-01 17:51:52,640 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\RegAsm.exe failed
2013-08-01 17:51:52,631 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngentask.exe failed
2013-08-01 17:51:52,630 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ngen.exe failed
2013-08-01 17:51:52,611 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\mscorsvw.exe failed
2013-08-01 17:51:52,559 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\MSBuild.exe failed
2013-08-01 17:51:52,542 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Microsoft.Workflow.Compiler.exe failed
2013-08-01 17:51:52,512 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\jsc.exe failed
2013-08-01 17:51:52,506 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\InstallUtil.exe failed
2013-08-01 17:51:52,500 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\ilasm.exe failed
2013-08-01 17:51:52,490 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\EdmGen.exe failed
2013-08-01 17:51:52,480 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\dfsvc.exe failed
2013-08-01 17:51:52,476 ERROR: Removing C:\Windows\Microsoft.NET\Framework64\v4.0.30319\DataSvcUtil.exe failed
It tried to take out all filetypes matching cfg.cleanup_list (.exe, .nfo, .nzb, .sfv, .srr, .srs, .txt, .url) on C: (the working and complete directories for downloads are both on H: while SABnzbd reports processing status: "Moving: ..." for much longer than usual. I don't run sabnzbd with admin persmissions, but it did clean out those file types from my C:\python27\python.exe directory.
It's running on a fresh Win 8 install with nothing installed to affect SABnzbd (but maybe these could: .NET 3.5, DirectX 9.0c, C++ redistributables x86/x64 '05, '08, '10, & '12), and is running from its Windows executable. SABnzbd has default install and user directory paths on C:. Temporary files are in D:\_temp\sys\ and in D:\_temp\usr\.
The only item of note from the logs is that line 676 in postproc.py is where the action happens. It's easily reproducible and multiple tests are the same with any combination of category or post-processing and with all .nzb's of this type (described below). Removing the filetype Cleanup List prevents the problem.
The only thing unusual about the .nzbs I've noticed cause SABnzbd to act this way is that they only have segments for a single .avi (not a file in segments to be joined in post-proc; a single file as assembled by SABnzbd downloading code) instead of a .rar set or any other files. The download directory for instance looks like H:\_temp\_usenet\5x21 - Slimer Streak.avi\ containing a 5x21 - Slimer Streak.avi and the __ADMIN__ directory upon downloading finish (before moving or post-processing of any kind).
SABnzbd 0.7.14 postproc.py's cleanup_list function seems to either receive a bad wdir or is unable to properly set path under these conditions (I don't know Python).
I hope this is helpful and if you need any info from me, I'll try to get back to you in a timely fashion.

