Hi everyone, I have a late 2013 MacPro and last week i did a software update to the latest MacOS High Sierra 10.13.4. When starting up my computer before the update i only heard the boot up or chime sound once...the way it should be. After the update i hear the boot up sound two times (directly following the first one). It does not always do this, i noticed that it usually does this when the comuter hasn't been started up for like a day or so. I did a hardware test but it came back saying there were no issues or errors found. Did a SMC reset but to no avail. I also made sure the the memory was well placed in the memory slots (just to make sure) but all seemed ok. Does anyone have an idea what the reason could be for this problem...again, it only started doing this after the software upgrade, never experienced this before. Are there any people out there whom have/had the same issue after the 10.13.4 upgrade. Anny suggestions on how to trouble shoot or solve the problem are most welcome. Thank you in advance and a nice weekend to all.