You almost never want to use this property.
When reading a zip file, if this flag is true (True in VB), the entire zip archive will be scanned and searched for entries. For large archives, this can take a very, long time. The much more efficient default behavior is to read the zip directory, which is stored at the end of the zip file. But, in some cases the directory is corrupted and you need to perform a full scan of the zip file to determine the contents of the zip file. This property lets you do that, when necessary.
This flag is effective only when calling Initialize(String). Normally you would read a ZipFile with the static ZipFile.Read method. But you can't set the FullScan property on the ZipFile instance when you use a static factory method like ZipFile.Read.
using (var zip = new ZipFile()) { zip.FullScan = true; zip.Initialize(zipFileName); zip.Save(newName); }
Using zip As New ZipFile zip.FullScan = True zip.Initialize(zipFileName) zip.Save(newName) End Using