A SCHEM file contains a custom arrangement of blocks comprising structures that can be placed within a Minecraft world. SCHEM files replaced .SCHEMATIC files with the release of Minecraft Java Edition 1.13. Minecraft Java Edition is the original version of Minecraft. SCHEM is a file extension created by Sponge, classified as Game Files.
You can open and edit SCHEM files using Minecraft mod tools like WorldEdit and Litematica. These allow players to create, export, and import SCHEM files within Minecraft Java Edition. You can convert SCHEM files to SCHEMATIC files for use in pre-1.13 Minecraft versions using SchemToSchematic or Mineways.
When you double-click a SCHEM file, Windows examines the filename extension. If Windows recognizes it, it opens the file in the associated program. When Windows does not recognize the extension, you receive a message to select an app to open the SCHEM file. Many people share SCHEM files without instructions on handling them. This can make it difficult to determine compatible programs for editing, converting or printing.