I purchased an iMac all-in-one machine in June 2018. An immediate problem I encountered was that the machine sometimes booted with no cursor. The mouse and keyboard are both wireless. The keyboard always worked, but the mouse was rendered useless whenever the machine booted with no cursor, which was intermittent. Turning the mouse off and on (after fully booting) generated a screen acknowledgment that the mouse status had changed but did not bring up the cursor. The voice assistant Siri was no help...
