** FYI Same issue in both Grummage and SBOMage **

My environment: Windows 11 64-bit, USA English

When opening an SBOM (in my case generated by Syft), the tools are failing to open the json due to not detecting/using the correct character encryption.

Error in SBOMmage

Original file open code:
with open(file_path, "r") as file:

Fixed for me (added encoding type)
with open(file_path, "r",encoding='utf-8') as file:

My fix would break it for others, so I'm not sure what the correct fix it to make it universal, but one I put the encoding param into the open method, the file opens and all works correctly.