[Obsidian Dragon]

Originally Posted by splicestudios

This problem was solved with a change of the mouse! I found an article discussing how Razer mice are built for windows and that they should be avoided for Mac... a USB mouse is a USB mouse, and the same model Razer Death Adder mouse worked great with a 2018 iMac, but the 2019 iMac Pro clearly had some incompatibility with the Razer mouse. A swap to a built-for-mac Logitech MX Anywhere 3 for Mac mouse and it's been great for 6 months and counting. Adding this reply in case there's anyone else out there chasing down something similar and would suggest looking at the mouse.

I suspect that since the Razer mouse is designed as a gamer's mouse, which are often Windows-based and also supports RGB lighting and additional buttons etc., that it is made to use some form of software driver in Windows. On a Mac that does not run the Windows drivers, the functionality is diminished (or in this case, not functioning properly). Some mice come with Mac drivers but my experience is that the drivers are not as robust as their Windows counterparts. Look for mice that are clearly marked as Mac compatible and ideally not require a software driver to be loaded. The bottom line: All USB mice are not the same.