A backup with zip64 is still failing with "Attempted to write a stream that is larger than 4GiB without setting the zip64 option"

[kenkendk]

@Cony

However, when I run the backup, it fails with the message “Attempted to write a stream that is larger than 4GiB without setting the zip64 option”:

That is an unfortunate error in 2.1.0.5:

ZIP64 seems unwilling to work in 2.1

Thanks for bringing this up. I have investigated a bit and it turns out that the new Zip compression (default) is capable of handling zip64 without any additional work. SharpCompress is also able to do this, but for legacy reasons require explicit opt-in to enable zip64 support (in case there is an ancient tool that needs to read the zip file). A bug introduced with the addition of the new zip library means that the flag is never actually set in SharpCompress, so any use of SharpCompress will…

The solution is to not set the zip64 option, which will the use the built-in Zip library that supports zip64. Canary builds mark the zip64 flag as deprecated, and always toggle Zip64 for SharpCompress.