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To save space, I packed personal files into .rar archive files with encrypted file names and a password – like this:

I wanted to keep the contents within them obscure by renaming those .rar files and removed the file extension (a BIG MISTAKE) before uploading them to Google Drive. I've since deleted the files on my PC to save space.

Here's what the .rar file with the file extension removed looks like:

I've uploaded a LOT of these .rar files (~50 GB worth). When I downloaded one and re-added the ".rar" to the end of the file, it said "The archive is either in unknown format or damaged" as shown here:

My own limited research told me the metadata/signature/Start Header & End Header of the file has been lost/corrupted and needs to be recovered before the .rar file's contents can be read. I modified the file in a hex editor (the first 6 letters) so that the WinRAR window would at least open, and got these error messages:

So after my dumb self tried countless methods of repairing the .rar file (inbuilt WinRAR repair feature/using 7zip DIDN'T WORK), it'd be a lifesaver if anyone had better experiences with any good .RAR/archive file recovery software that they'd recommend, or methods to repair this.

  • 1
    Might there be a problem with \r\n versus \n usage. Did you use the same computer to upload and download the file? Just do a small test make a new small rar file, remove the .rar upload file as you did before download the file as you did as well and have a look at the size in bytes. When downloaded and smaller use unix2dos when larger use dos2unix when this rick does not work look with a hex editor in the file and try to figure out the problem. – albert Aug 3 '18 at 15:26
  • I used different computers at different locations. I tried a test (all on one computer) and cannot reproduce the corrupted file – there was no difference in size either. As for unix2dos/dos2unix to fix my file, I'm not sure what I should be doing with this program – could you guide me through this please? (I'm on Windows 7 if that's relevant) – user39823 Aug 3 '18 at 17:45
  • The Windows 7 is just marginal important. You wrote "I used different computers at different locations" is this for the uploading part and the downloading is on your "current" computer? The computer(s) for the uploading what kind of OS was running on it? Regarding the dos2unix / unix2dos these are 2 programs to handle problems with \r\n versus \n There are a number of implementations of it also for Windows 7 in stackoverflow.com/questions/20368781/… there are also some other alternatives (like Notepad++) for the conversion. – albert Aug 3 '18 at 17:51
  • The file that is corrupted was uploaded from my laptop, and the downloading is on the PC I'm using now, both running Windows 7. As for using dos2unix / unix2dos how do I perform this conversion of the corrupted file to fix this \r\n versus \n? I can also use Notepad++. – user39823 Aug 3 '18 at 17:59
  • When it is the \r\n issue it is easy to use dos2unix / unix2dos by means of e.g, dos2unix <file> NOTE this is an inplace operation!, but I think the WinRar Repair Kit is even a better option to try (I never looked at it; I never had problems with rar files so-far). – albert Aug 4 '18 at 8:39
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WinRar Repair Kit may be an option.

WinRar Repair Kit is an all-in-one, fast and extremely efficient WinRar Repair tool intended for quick and completely unassisted recovery of files and folders from corrupted RAR archive file...

...was designed for maximum accessibility and comfort of use, hence the simplicity of its user interface based on a step-by-step wizard. All the user needs to do is to select the damaged source file, wait for the program to analyze its contents and specify the destination folder to be used for recovery. This corrupt RAR file repair software uses an innovative core that leverages the power of several advanced algorithms to turn RAR file repair into a task that virtually anyone can handle without any problems.

... Additional features of WinRar Repair Tool include the support of self-extracting (SFX) archives, multi-volume (split) archives, files with broken CRC values, and files larger than 2 GB.

  • Thanks, have you used it before or know if it prompts you to pay for it after it scans your file? – user39823 Aug 3 '18 at 23:21
  • Software is a terrible waste of time; spent 10 days of my PC running to repair a 9 GB file only for it to request $27 for a "free-to-try" product. Worse yet, it restarts itself when inputting a license key (I put in gibberish), wasting its own effort in "repairing" the file and making you start over. It also produces barely readable files that seem useless: i.imgur.com/SiWyw75.png – user39823 Aug 14 '18 at 12:30
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You might want to try opening the RAR file with the 7-zip archiver. (https://www.7-zip.org/)

7-zip can extract RAR files. And unlike WinRAR, which appears to give up if it sees a problem, 7-zip will open the archive and extract whatever it can, with errors shown for damaged files it can't extract.

These days, I use 7-zip as my standard archiver. It creates 7z, XZ, BZIP2, GZIP, TAR, ZIP and WIM files. It extracts AR, ARJ, CAB, CHM, CPIO, CramFS, DMG, EXT, FAT, GPT, HFS, IHEX, ISO, LZH, LZMA, MBR, MSI, NSIS, NTFS, QCOW2, RAR, RPM, SquashFS, UDF, UEFI, VDI, VHD, VMDK, WIM, XAR and Z.

7-zip's compression is as good as RAR's, and the 7-zip engine has been ported to Linux, OS/X, and Android, so I can deal with 7z files on any device I use.

0

I don't think you can fix a compressed file which gives you error while extracting. Try downloading the file using another software, Google Chrome¹, Internet Download Manager², XTreme Download Manager³ and aria2⁴ works fine for me. In your case right click the file and click "Compressed (zipped) folder" on Windows to prevent compatibility issues in the future. Or use the default program and the file format that your OS comes with.

Screenshot for Compresssion


¹ Google Chrome (commonly known simply as Chrome) is a cross-platform web browser developed by Google. It was first released in 2008 for Microsoft Windows, and was later ported to Linux, macOS, iOS, and Android. The browser is also the main component of Chrome OS, where it serves as the platform for web apps.

² Internet Download Manager (also called IDM) is a shareware download manager. It is only available for the Microsoft Windows operating system.

³ Xtreme Download Manager is a powerful tool to increase download speed up-to 500%, save and convert streaming videos from YouTube, Vimeo, Dailymotion, Google Video and thousands of other websites, resume broken/dead downloads and schedule downloads.

aria2 is a lightweight multi-protocol & multi-source, cross platform download utility operated in command-line. It supports HTTP/HTTPS, FTP, SFTP, BitTorrent and Metalink.

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