This will cover unpacking the LegacyMapMul.UOP files from the Ultima Game Client folder, to the old standard Map.MUL file types using UOFiddler. You can find UO Fiddler on this thread: http://www.playuo.org/emu/index.php?threads/uo-fiddler.139/ With UO Fiddler open, at the top right side of the User Interface, you will find two little arrow icons < > that allow you to scroll through the available plugins. The UOP Packer is the very last plugin listed using the right arrow. Select or press the UOP Packer tab. Now we want to open our Ultima Online Installation folder, and find the Map files. They are the following files: map0LegacyMUL.uop map0xLegacyMUL.uop map1LegacyMUL.uop map1xLegacyMUL.uop map2LegacyMUL.uop map2xLegacyMUL.uop map3LegacyMUL.uop map4LegacyMUL.uop map5LegacyMUL.uop The files with the X are now the replacement files for the old MapDif files, that hold any small difference's to the map. I do not know the absolute reason or specifics to this, but I believe they are for temporary differences to the map that OSI/BroadSword wants to make, rather than changing the real map. These are needed as well. Make a new folder in your UO Fiddler folder for this set of map files. For this example, I made a folder named OSI_maps Copy the map files listed above (or just the ones you want to unpack) from your Ultima Online folder to this new folder, and then copy the address from the address bar of this folder. (this makes things easy for next step) Now, we pull the UO Fiddler back up. Paste the address of the folder with the maps into the text field of the UOP Packer screen. *You can just use the browse button as well to find the folder* And then select the Extract UOP to MUL selection. Press the big Start bar to begin the unpack process... This will take a few moments, and there will be a status at the bottom left of the process as it happens. When finished, you will see the status area show: Done (9/9 files extracted) Now you can pull your folder back up and check your new files. You should have the following new files.. as well as the UOP set you started with. Map0.mul Map0x.mul Map1.mul Map1x.mul Map2.mul Map2x.mul Map3.mul Map4.mul Map5.mul You now have a set of map files to use as you wish. This process would be the same should you want to reverse, and Pack the MUL files to UOP by simply selecting the other button, Pack UOP to MUL on the UOP Packer plugin page. There is another tab that is for packing/unpacking a single file, however this page will work a single file as well as a group of files just the same. I actually use the Every File option of the UOP Packer for a single or group of files myself. Hope that helps! This is not specific to just the Map files, as it is the same process should you want to unpack/pack the Gump, Art or Sound files too.