To troubleshoot issues with a .skel file, you need to ensure that you are using the exact version of Spine that was used to export the file. If the file is not opening, it could be due to a version mismatch or the file being corrupted. You can check the version by opening the file in a text or hex editor to see if the version number is visible in the first few bytes. If the file is from an older version of Spine, you may need to revert to that version to import the file successfully. Additionally, ensure that the file is not mistakenly in JSON format with a .skel extension, as this can cause import issues.

0983164177 The file you have attached looks quite different in format from the .skel file exported from Spine: the .skel file exported from Spine looks like this when opened in a text editor:

The .skel file you have attached looks like this:

Ask the person who provided you with that .skel file for more information.