Hello, all. I'm new here, so please take it easy on me. I've read through this thread from the start and despite a couple mentions on the first page starting with rasim, it isn't clear whether these user-defined functions will work with the latest version of 7za.dll (official 7-Zip Library). Rasim links to a rather ancient discussion of problems with a much older version of the DLL. GEOSoft seems to have had some experience with 7za.dll, but doesn't specify which versions or how long ago he's tried. A much more recent mention of the use of the DLL that I found with a google search seems to confirm some difficulties in its "Known Issues" section, yet further down states the following: Personally, I'm just interested in a more recent version than the one linked in rasim's first post which is over two and a half years old.