I downloaded last night the Unrar lib and inc and found that somethings are different from the C# header fle. The OpenArchiveDataEx struct in C has for the ARCName and FileName ? dup(0) and in the asm include it's just a pointer. Also something that is necessary to decrypt a password protected is the Callback member which doesn't exist in the include. The last member is reserved and has in the inc dd 32 dup(0) and in the C# header 28 dup(0). I imagined i could insert those 2 missing members and decrease the reserved member but it doesnt seem to work. Has anyone been around this? Thanks