In the vast majority of cases, multikey.sys is legitimate – provided it came with your hardware or a trusted application.
However, because it’s a kernel driver (it runs at a very low level of Windows), it has high system access. Malware authors have occasionally used similar filenames to hide rootkits. multikey.sys windows 11
If you no longer use the related hardware: In the vast majority of cases, multikey
If the file is legitimate (e.g., from a gaming keyboard): Uninstall the software
multikey.sys automatically.