Yesterday it was brought to my attention that SigCheck 2.2.0 had regressed substantially from the previous release (SigCheck 2.0.1), with a nearly empty vignette. This situation has now been rectified, so please use SigCheck 2.2.1 or later (or 2.3.1 on the development branch). I apologize for any inconvenience.
Also note that the Mac and Windows binaries have not yet been automatically rebuilt, so you will have to wait a bit before that happens, unless you can install them from source. I will update this thread as the new binaries become available.
P.S. I have also added a section to the vignette explaining how to get known gene signatures from MSigDB (Broad GSEA). You have to accept their licence and download the signatures.