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Could not restore a file's security information from the zip file because the security descriptor was compressed using an unknown compression method.
The library supports security descriptors compressed with the deflate algorithm. It is conceivable, although unlikely, that there are some libraries or applications that may attempt to compress the security descriptor with another compression algorithm that was used in previous versions of the zip file format. If this is the case, library will unzip the file anyway, but without restoring its security information. If you come across a zip file that produces this warning, we suggest you contact Xceed Software and let us know.