Hi Luigi 1) The file to compress is about ~ 1.6Gb. (1.600.000.000 Bytes) I have found that the file limit is just slightly more than 500MB except where the compression level is 0 then any 'File system' supported size is okay, i.e. no compression (better for avi files anyway). For files > 500MB (or larger than the destination media) I use the zlib unit (TCompressionStream) that came with Delphi (I do not know if this came with C Builder). This is where the ability to zip streams with zipdll would have been handy as we could have zipped very large files in sections. Regards Barry