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Bug 32725 - Creating a new System.IO.Compression.ZipArchive fails on mono with SharpCompress.Common.ArchiveException
Summary: Creating a new System.IO.Compression.ZipArchive fails on mono with SharpCompr...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System (show other bugs)
Version: 4.0.0
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: João Matos
Depends on:
Reported: 2015-08-03 15:39 UTC by Rasmus Hansen
Modified: 2015-09-05 10:34 UTC (History)
4 users (show)

See Also:
Is this bug a regression?: ---
Last known good build:


Description Rasmus Hansen 2015-08-03 15:39:55 UTC
Attempting to create a zip archive results in "SharpCompress.Common.ArchiveException" "Failed to locate the Zip Header".
I made a minimum working issue:
This will crash on line 37 if ran under Mono. 

The method when run under normal .Net on windows. 
Tested with Mono nightly build for Mac and Mono 4.0.2 stable for Mac.
Also tested with Mono from github on Linux 8/3/2015. 

Exception doesn't happen if ZipArchiveMode is set to Create instead of Update.
Comment 1 David Schulte 2015-09-04 07:00:42 UTC
A simple fix for this issue may be change ZipArchive's Open() method to test to see if the size of the archive file (or stream) is of length 0 before attempting to read the archive directory or other content.

Due to some other issues with Xamarin's implementation of ZipArchive, I've written a replacement that keeps the same API as ZipArchive, but is based on ZipStorer. My implementation of ZipArchive.Open() does this and works fine.

Is there any update on when this issue might be addressed?
Comment 2 João Matos 2015-09-04 10:24:41 UTC
Pull request up at

Will backport this to 4.2 and 4.0 once its merged.
Comment 3 João Matos 2015-09-04 10:25:11 UTC
Also please also report the other issues you've faced so we can get them fixed.
Comment 4 David Schulte 2015-09-04 10:30:30 UTC


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