Same here. From: C:\Users\<user>\AppData\Local\Temp\PDApp.log:
<errorType>LongPathError</errorType>
<filePath>C:\Users\<user>\AppData\Local\Temp\{839FDA1E-684B-4164-A8A0-AC83A4D37D3F}\AICY\ LS20\10.0\InCopy_10_LS20_Win32
I can manually extract the zip file from: C:\Users\<user>\AppData\Local\Adobe\CCP\AdobeCCPCache\AICY\LS20\InCopy_10_LS20_Win32.7z to the above path (which I think is what it's trying to do) with no error, so it seems to be something Adobe is going to have to fix.
Someone else worked around it by creating a local user with a single character as the user name: Creative Cloud Packager Keeps Failing on InDesign: "Maximum File Path Name Exceeded"