Good point re WinRAR and the "recovery record". I vaguely recall that as being amongst its list of features when I used to use it some time ago.
I just now did a DuckGo search on "Repair corrupt ZIP"
and came up with several hits, including this interesting one about ZIP Repair Pro
Repair Zip Files using Zip Repair
Zip Repair is a utility that will repair corrupt Zip files. Usually a corrupt Zip file gives the error message:
"Cannot open file: it does not appear to be a valid archive"
Zip Repair creates an error free backup of your original file for instant access, or you can extract files directly from a corrupt ZIP file to your hard drive. No special skills required. A simple user interface with full install / uninstall support.
- New: Repair a Zip file or extract files directly from the ZIP
- New: Zip Repair will fix CRC errors in .zip files so that data can still be uncompressed
- New: Zip Repair supports spanned zip volumes. You can now repair and extract from a spanned zip set even if part of the set is missing
- New: Full support for the Zip64 format
- New: Support for huge file sizes 2GB+ (as long as you have the disk space)
- New: Batch repair multiple ZIP files
It doesn't say whether it can recover all
of a corrupted ZIP file's contents 100% of the time, but it could be worth a try if you are stuck with a truly corrupted file that (say) 7-ZIP cannot open/read or where other approaches suggested above have drawn a blank.
A year or so past, I downloaded a corrupted executable install file for Stickies. It executed fine but wouldn't install properly - the install got stuck in a program loop. So I asked the author (Tom Revell of Zhorn Software) about it and he was mystified. He sent me a ZIP file (which installed just fine) and asked me to send him a copy of the installer file that I had downloaded. It turned out that it had a different checksum to the one on the download server, so it must have got corrupted in transmission, somehow, and yet it still executed with no error message.
After that experience, I now usually look for the checksum of downloaded executable and other archive files, for file verification, and also - just in case - try to open and test them using 7-ZIP.