As what may be the most common and convenient way to store and send multiple files, the ZIP file format is used by essentially everyone online. That being the case, there’s a good chance you’ll eventually come across one that has been corrupted, not least because only a single corrupt bit in one file out of dozens inside the ZIP could prevent your file archiver from opening or extracting its contents.
Corrupt files can result from a variety of issues including bad drive sectors, malware, an incomplete download or transfer such as during a drop in your connection, or any other sudden interruption like a power failure or an improper shut down while working with the ZIP file.
A corrupt ZIP file may open for you anyway, but some of the original files might be missing and attempting to open damaged ZIPs typically causes Windows to prompt with the following error:
“Windows cannot open the folder. The Compressed (zipped) Folder ‘C:\Users\TechSpot\Desktop\Wallpaper Collection Corrupt.zip’ is invalid”
We recreated a corrupt ZIP file by archiving an old collection of wallpapers and deleting parts of the file’s code using a hex editor (Notepad++). In doing so, our collection dropped from nine images to one and we couldn’t actually open the file even though it was still being displayed in the file explorer.
Your rate of success recovering anything from an archive will vary depending on the tool you use, the contents of your ZIP and the degree to which it has been corrupted.
Starting with the software that you are most likely to have installed already, WinRARprovides a built-in repair tool for damaged ZIP files. Open the file, then go to Tools > Repair archive. WinRAR managed to recover seven out of the nine files from our damaged archive. However, the software is only free for 40 days, after which a license to continue using the software will cost you about $30.
— from www.techspot.com