Always read the map’s included Readme.txt . If the creator spent 100 hours scripting the mission, you can spend 60 seconds reading the install notes.

Install the latest community patch. Many old maps require SSF version 2.1 or higher. Find the "SSF All-in-One Patch" on Sudden Strike Center.

Move the map from \MapsMP to \Maps (or vice versa). Some creators mislabel their files.