Continued messing with this since I now HAVE NO cc desktop... So far I've found several topics with lots of notes, and LOTS of majorly pissed off people, but absolutely no actual answer from Adobe. Looked at several other topics that purport to have solved the problem:
1. Reboot system into safe mode with network. Install cc - exactly the same 205 error.
2. Run AdobeCreativeCloudClearnerTool THEN reboot into save mode with network. Install CC - EXACTLY the same 205 error.
3. Turn Windows Firewall COMPLETELY OFF. Install CC - EXACTLY the same 205 error.
4. Follow Jeff Wrights instruction from June 19,2014: "for information on how to resolve Error 205 please see Error downloading Creative Cloud applications - http://helpx.adobe.com/creative-cloud/kb/error-downloading-cc-apps.html."
I found "Download 205 When segment validation fails again and again, the file is assumed to be invalid."
I'm NOT on a managed network.
I AM using a wired connection.
I ROUTINELY download files in the hundred+ megabyte range, and frequently in the gigabyte range.
The system hardware hasn't changed since the last umpteen times Adobe CC updated. The system SOFTWARE hasn't changed since the last umpteen times Adobe CC updated.
I looked at the download logs and at the end, after repeatedly stating the the job is in STOPPED_STATE, it gets:
07/07/14 14:33:41:512 | [ERROR] | | | | | | | 4240 | download job: failed to validate the segment (0)
07/07/14 14:33:41:512 | [ERROR] | | | | | | | 4240 | the download job (0) failed to execute. The job state is STOPPED_STATE
07/07/14 14:33:42:151 | [INFO] | | | | | | | 2332 | Retry count overshoot for ERROR_SEGMENT_VALIDATION_FAILURE - 11
07/07/14 14:33:42:167 | [INFO] | | | | | | | 4240 | the download job (0) is cancelled