"I've been installing Grub Customizer on clients machines almost as long as I've been encouraging users to transition from MMI (Microsoft Malware, Inc.) as soon as humanly possible. Grub Customizer absolutely ROCKS! - As long as it is configured properly. I'd bet big $$$ - most users that experience issues are caused by 1.) working too fast &/or not giving the system ample time to settle. 2.) Attempting to perform too many functions & not taking the time to "Re-Boot" & review edits. 3.) Combine - Editing the Grub Customizer while “at the same time” having a "Terminal Window" open making multiple edits back & forth simultaneously. I have made all these errors in judgment. But if LM users slowdown a bit, allow Grub Customizer to operate properly it will become one of BEST TOOLS in the TOOLBOX! JMHO, Be well, Douglas Swinhart Systems Administrator (semi-retired 40+ years servicing small / medium sized businesses)"