Zip file unconfirmed download

The Wikipedia entry on ZIP states that originally the format had a 4 GiB limit on the total size of the archive as well as both the uncompressed and compressed size of a file.

To be sure, I verified that both unzip and 7-zip on my machine support ZIP64 1. I did some additional tests to verify if my problem could be a ZIPrelated issue. Both were able to extract the file without any issues.

I then tried to extract both files with both unzip and 7-zip i. I extracted each file with both tools. Again, both extracted these files without any problems. The zip tool has a switch that can be used to test the integrity of a ZIP file. I ran it on the problematic file like this:.

The Python programming language by default includes a zipfile module, which has tools for reading and writing ZIP files. Here, its value is 0, which is the correct and expected value. Also, a check on the 8 GB ZIP files that I had created myself with zip and 7-zip showed both to have a value of 1 for this field.

The most likely explanation I could think of, was some difference between my local version of the Python zipfile module and the latest published version on Github. This revealed a recent change to zipfile : prior to a patch that was submitted in May , the offending check was done slightly differently:.

Note that in the old situation the test would fail if disks was any value other than 1, whereas in the new situation it only fails if disks is greater than 1. Given that for our OneDrive file the value is 0, this explains why the old version results in the error.

The Git commit of the patch also includes the following note:. Added support for ZIP files with disks set to 0. Such files are commonly created by builtin tools on Windows when use ZIP64 extension. So could this be the vital clue we need to solve this little file format mystery? Re-running my Python test script with the latest version of the zipfile module did not result in any reported errors, so this looked hopeful for a start. The modified ZIP file passed all these tests without any problems!

The contents of the file could be extracted normally, and the extraction is also complete. If a widely-used platform by a major vendor such as Microsoft produces ZIP archives with major interoperability issues, I would expect others to have run into this before.

More details about this are available here , here and here. The tests presented here demonstrate how large ZIP files exported from the Microsoft OneDrive web client cannot be read by widely-used tools such as unzip and 7-zip. Well it has degenerated my entire file system duplicated. DLL files all over my desktop and some programs seem to work fine while others don't even have a shortcut on the desktop anymore. I've done some minor research online and have some basic and general idea of what is happening but I work online and have a big deadline that involves a lot artwork and graphic design that represent many work hours and I'm trying to decide after trying a restore point and a reset both of which stabilized my machine but, so much of the data could be corrupt and most links or shortcuts aren't working correctly I feel like I should do a clean install but in doing so, I lose my work.

Or, is it possible to scan each file or folder to make sure its not contaminated??? Was this reply helpful? Yes No. Sorry this didn't help. Thanks for your feedback. Choose where you want to search below Search Search the Community. Search the community and support articles Windows Windows 10 Search Community member. This thread is locked.