If you don't think you have the latest update, you can also verify it by going (within the Steam App)to Library/Software/GameGuru and right clicking, go down to properties, and clicking on the "Local Files" tab and then click on "Verify Integrity of Game Cache" That should force any updates and as a side note, this can come in handy if you experience weird phenomena in any Steam program. Lock this info away, just in case!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 10/64, GeForce GTX 1080 (Passmark 12735); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 10/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics