Windows ZIP File Size Limits
- A ZIP file holds up to 65,535 files. Adding large numbers of files to a ZIP archive may take up a lot of system memory while the program compresses them. When compressing multiple files into one archive, you should add the files in groups so the computer has the ability to release the memory or make it available to other tasks if you're also doing other things on the computer.
- Each file may be up to 2^32 - 1 bytes before the user adds it to a ZIP archive. However, the archive itself not not exceed this same size. Similarly to the considerations regarding the number of files, the issues with memory management are also a risk with large files. Add large files to an archive in small batches to avoid freezing the computer or slowing down other processes.
- A segmented archive is a ZIP archive that is broken into multiple files, either by spanning or splitting. A spanning archive segments an archive and allows the user to store different parts of the complete archive in several different places, for example CDs, but each segment cannot exceed 999 bytes. A split archive works similarly, but segments must be contained in the same directory if the user wants to decompress the archived files. Segments in a split archive may be up to 65,535 bytes.
- The ZIP64 format improves on the limitations of regular ZIP files. The number of files an archive holds, size of any of those files and total size of the archive limit is 2^64 - 1 bytes. In a segmented archive, it can hold up to 2^32 - 1 segments. Segments cannot exceed 2^32 - 1 bytes for both spanned archives and split archives. ZIP64 is implemented on the Windows Vista and Windows 7 operating systems, but not on Windows XP, although some programs do support this format even on XP.