>>>>>I have not tried it, but what happens when a tool such as WinZip (32 bit version) tries to create a zip greater than 2G? I would suspect that the problem is with 32-bit and the ability to access files greater than 2G in size (2**32). If this is the case then you will have to use a shell command and a 64-bit version of a zip compressor to create the zip archive file that is greater than 2G. You cannot call any active-x component that is 32-bit to create files greater than 2G.
>>>>
>>>>I wonder if that is true? I could zip a file larger than 2.5 GB, so the limit is not at 2G, which means it has nothing to do with 32-bit.
>>>>I will try the shell command, but it will be much more work to integrate, so I was hoping for some other third party tool that I could use.
>>>
>>>Another question - what is the size of the resulting zip file when you zip a 2.5GB file? That may well be less than 2GB. But, maybe when you're zipping a 3GB file, the result wants to be greater than 2GB.
>>>
>>>Exactly how large is the "corrupt" zip file?
>>
>>The resulting zip files are well below 1 GB, mostly around 300 - 500 MB
>
>Have you tested on multiple machines?
>
>Somewhat related, you might want to test with AV real-time scanning disabled.

Yes, it's the same on all machines, that's how we found it out because it happened at a client.
I have usually AV disabled on my development machine, so that has nothing to do with it.