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I have huge 12 GB .sql.gz file that I need to unzip on my Windows 10 computer. So far, I have tried using WinZip, 7-Zip, and the gunzip command in Cygwin. I received the error messages shown below for each of those attempts.

I know that the error messages indicate that this file is invalid, but I'm not sure whether these messages are due to the fact that it is so large, or that the file is actually corrupt; the file download process appeared to complete successfully, although it is possible that even a corrupted file would not show any indication that the download process was corrupted.

When try to open with WinZip, the error message is:

Cannot open file 'file_v1.2.sql.gz'. It does not appear to be a valid archive.
If you downloaded this file, try downloading this file again.

When try to open with 7-Zip, the error message is:

Cannot open the file as [gzip] archive
Is not archive

When try to open in Cygwin using gunzip, the error message is:

gzip: file_v1.2.sql.gz: not in gzip format

I have been looking for additional potential solutions to this issue online, but so far haven't located any useful suggestions. If anyone has ideas about what might work, I appreciate your input.

Giacomo1968
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Bob Loblaw
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1 Answers1

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You could try Gzip for Windows, i.e., run it outside of Cygwin, though, I would suspect that if you received an error message under Cygwin, you would receive a similar error message again. Another alternative is the free Zip Reader from Pkware, which can uncompress a variety of compressed file types, including the gzip .gz files, though it doesn't provide any compression capabilities. You will be prompted to provide an email address to download it, but there's no need to confirm an email address; when you submit the form you are immediately taken to a page where you can download the software. You could also try WinRAR, since it can decompress .gz files.

A valid gzip file should have a 10-byte header containing a magic number (1f 8b), a version number and a timestamp. As a check on whether the file is a valid gzip file, you could check the file with a hexadecimal editor to see if the file has such a header. On Microsoft Windows systems, I use the Freeware Hex Editor XVI32, but unfortunately, due to the size of the file, that likely won't work in your case, since the developer states in its feature list "XVI32 allows to edit files up to 2 GB (enough virtual memory provided, of course)." UltraEdit can be used as a hexadecimal editor; the developer states "Regarding large files, UltraEdit handles files in excess of 4GB. UltraEdit is disk based. This means it only loads small portions of the file at once into memory so it does not use all the memory and stop other applications from running. However, it does make a temporary copy of the file to achieve this and this can take time for large files." I haven't used that product myself, but it is free for a 30-day trial period. If the file doesn't have a valid header, it probably can't be processed by any program that uncompresses .gz files.

moonpoint
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