Note: This fix will disable ALL Onstar services. I recently purchased a 2015 LTZ hatchback. Right after I bought it I noticed the MyLink clock would not keep the correct time. It didn't matter if I set it using "auto-clock sync" or manually. The car is still under warranty so I took it to a dealer who reset it and told me the "fix" might not stick as the clock is controlled by Onstar. He told me I would have to contact Onstar and agree to their terms and conditions for a "2-year free trial." This would be my "fix" for the clock. I chose not to contact Onstar. I went 6 weeks with no clock problems. I started my car a couple days ago and was blasted by a voice coming through my audio system saying,"This car is equipped with Onstar. Please press the Onstar button to activate your service." From that moment on the MyLink clock would no longer keep accurate time. I want nothing to do with Onstar and greatly resent such tactics. I think it's probably illegal for Onstar to hold my clock hostage in order for me to sign up for their services. The easy fix for this is to simply pull the Onstar fuse (fuse #15 in 2015 Sonics). Now my clock works just fine by setting it manually and I can look forward to no more invasive advertisements from Onstar blasting through my speakers. I hope this helps others who have similar problems.