Ugh, this just happened again after doing pkg>update.
From various workers:
ERROR: LoadError: IOError: unlink: resource busy or locked (EBUSY)
ERROR: LoadError: LoadError: Failed to precompile GR [28b8d3ca-fb5f-59d9-8090-bfdbd6d07a71] to C:\Users\nicho.julia\compiled\v1.4\GR\NDU5Y_CqdxD.ji.