[ { "Id": "131343", "ThreadId": "39585", "Html": "Hi,
\r\n
\r\nI wish to write a app for me, that get´s my database backups (Zip File) and extract them.
\r\nThe Files are over 500 MB big.
\r\nEvery time I try to extract the file, I get the Error:
\r\n"xxx is not a valid zip file".
\r\nWith lower files, e.g. 20 MB I have no problems.
\r\n
\r\nCan anyone help me?\r\n", "PostedDate": "2008-11-10T05:58:25.287-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "131472", "ThreadId": "39585", "Html": "If you give me a sample of a zip file that causes the problem, I can look at it.
\r\nI realize there may be data privacy issues.
\r\n
\r\nAlso, how did you create the zip file?  Did you use DotNetZip?  Or was it created with some other tool or library?
\r\nif so , which one? 
\r\n
\r\nthanks. 
\r\n 
\r\n", "PostedDate": "2008-11-10T11:44:51.317-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "131480", "ThreadId": "39585", "Html": "Hi,
\r\n
\r\nI´m sorry but I can´t give you an exmaple, we must do it without.
\r\nIt was created by a automaticly WinRAR Script, but it is a ZIP File.
\r\nIts 550 MB big and extracted over 4-5GB\r\n", "PostedDate": "2008-11-10T12:23:51.777-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "131498", "ThreadId": "39585", "Html": "Unfortunately I will have a tough time understanding what is wrong with the zipfile without even a stack trace of the error.
\r\nTo track it down, I really need the actual zip file that causes the problem.
\r\n", "PostedDate": "2008-11-10T13:55:27.483-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "131959", "ThreadId": "39585", "Html": "For what it's worth, I tried extracting a 954MB text file compressed using WinRar (Best-zip compression) and it extracted just fine. The zip file size was 948KB and only contained that one text file. There might be something wrong with your script and the file is actually using rar compression. When I use a rar-compressed file I get that exact error.
\r\n
\r\n", "PostedDate": "2008-11-12T03:19:26.347-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "132912", "ThreadId": "39585", "Html": "I think it is a common issue with WinRAR
\r\n
\r\nHad the same errors with the application AutoUpdate+ that it could not unzip Zip files created with WinRar.
\r\nTry creating the same Zip file manually and zip it with the windows native Zip program. It should be able to extract it.
\r\n", "PostedDate": "2008-11-16T07:31:12.78-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "132917", "ThreadId": "39585", "Html": "It could be, as JohnAndre suggested, that the file is not actually a zip file, compliant with the spec, but is instead a compressed archive that only WinRAR understands. 
\r\n
\r\nIf I had the zip file in my hand, I would be able to tell.
\r\nWithout it, I cannot fix the problem.\r\n", "PostedDate": "2008-11-16T08:00:49.293-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133348", "ThreadId": "39585", "Html": "Hi,
\r\n
\r\nI found a little bit more:
\r\n
\r\nThe file over 500 MB can not make to a ZIP File, either with WinRAR nor with Windows native ZIP.
\r\nEvery time I get the message "It´s too large".
\r\nSo I think it can be a RAR-File that is renamed or something mysterius else.\r\n", "PostedDate": "2008-11-18T03:03:22.707-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133349", "ThreadId": "39585", "Html": "Here are the Stack Trace:
\r\n
\r\n   at Ionic.Utils.Zip.ZipFile.ReadIntoInstance(ZipFile zf)
\r\n   at Ionic.Utils.Zip.ZipFile.Read(String zipFileName, TextWriter statusMessageWriter, Encoding encoding)
\r\n
\r\nAnd here are the Excaption:
\r\n
\r\nInnerException = {"  ZipEntry::Read(): Bad signature (0x7B99EC00) at position  0x00000050"}\r\n", "PostedDate": "2008-11-18T03:03:30.45-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133438", "ThreadId": "39585", "Html": "Kovu, thanks -
\r\nThat file appears to be either
\r\n\r\n
\r\n", "PostedDate": "2008-11-18T09:41:58.37-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133463", "ThreadId": "39585", "Html": "Hi,
\r\n
\r\nTo check if it's a ZIP file, and if you find a way to open your file with text editor (not sure that you can open a 500MB file), check the first 2 chars of the file, if you have PK, that's mean that this is a PKZIP file (so a ZIP file).
\r\n
\r\nA rar file begins with : Rar
\r\n
\r\nAs Cheeso says, even if it's a Zip file, the file can be corrupt.
\r\n
\r\nWinrar should be able to open a Zip64 archive.\r\n", "PostedDate": "2008-11-18T11:48:09.883-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133541", "ThreadId": "39585", "Html": "DomZ - that's right.
\r\nBut if the error Kovu is seeing, is a "bad signature" at position 50 in the file, then the PK characters have been found in the header of the file.
\r\n
\r\n", "PostedDate": "2008-11-18T19:39:19.1-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133582", "ThreadId": "39585", "Html": "Ok,
\r\n
\r\nfirst:
\r\nhttp://www.pictureupload.de/originals/pictures/191108085622_2008-11-19_084431.png
\r\nThis is one of this large files in WordPad. You see: It begin with "PK".
\r\nSo it seems to be a ZIP.
\r\n
\r\nsecond:
\r\nNo other DotNet ZIP Libary can open it, I try some of them.
\r\nThe Error-Handling in them seems worse then yours and throw a default error.
\r\n
\r\n", "PostedDate": "2008-11-18T23:47:29.89-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133663", "ThreadId": "39585", "Html": "If no package can open it, then it seems unanimous that it is not a valid zip file.
\r\nit seems to be corrupted.
\r\n
\r\nif you could give me a hex dump of the first 0x200 bytes I would be able to tell you more.
\r\n
\r\nThere are "Zip fix" tools out there, I think. I've never used any.  But they say it is possible to repair corrupted zip files.
\r\n
\r\n", "PostedDate": "2008-11-19T08:34:51.377-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133860", "ThreadId": "39585", "Html": "I don´t think it´s corrupt.
\r\nBecause I can unzip it manualy with WinRar and Windows Native Zip. But not zip again, because it´s to large.\r\n", "PostedDate": "2008-11-20T00:57:47.053-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133907", "ThreadId": "39585", "Html": "Ok, in the "Info" Button in WinRar I found out that is a ZIP64 File!
\r\nIs it possible to get it extract?\r\n", "PostedDate": "2008-11-20T05:45:45.617-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "133954", "ThreadId": "39585", "Html": "no, DotNetZip does not do Zip64. 
\r\nIt is an active workitem.
\r\n
\r\nOne of the first things I will do is modify the library to detect zip64 and throw a proper exception, noting something like "Zip64 is not yet supported."
\r\n", "PostedDate": "2008-11-20T09:20:59.86-08:00", "UserRole": null, "MarkedAsAnswerDate": null }, { "Id": "141857", "ThreadId": "39585", "Html": "Kovu - can you get me that zip64 archive produced by WinRAR?
\r\nI'd like to try to embed support for zip64 in the library, and I need tests.\r\n", "PostedDate": "2008-12-19T07:26:38.03-08:00", "UserRole": null, "MarkedAsAnswerDate": null } ]