cpgz file

The file is corrupt.

I had this problem too. It turned out that I was trying to unzip a .zip file before it had completely downloaded from google docs - it was a large file and it took a couple of minutes to download. There was no indication that the download was in progress, so I immediately clicked on the .zip file as soon as it appeared on my desktop. When you try to unzip an incomplete .zip file, a .cpgz file is created. No idea why. I then got off track trying to do something with the .cpgz file per the many hints found by googling. Finally I looked at file sizes and saw that while it was downloading, the .zip file was zero bytes, but there was a .zip.part file that was bigger and bigger. Once the download completed, the .part file went away and I was able to successfully unzip the .zip file.

So ... your .zip file is either corrupted, or it hadn't finished downloading when you tried to unzip it. Use a terminal window and check the file size (ls -l) and/or use the 'file' command.

I encountered this problem for the first time today. Unzipping just produced a .cpgz file, which would unzip to a .zip, which would unzip to a .cpgz ...

None of the proposed diagnoses or solutions I found on the web worked either. The file was neither too large nor unfeasibly small, it had finished downloading, neither finder nor stuffit expander would do it.

Then I found buried away in a post a link to The Unarchiver. It's free, and it worked.

UnRarX would do it too, but bottom line is, if the zip file is over 2GB, the native apps within OSX won't expand it and behave as you saw.