Finder crashed and can't force quit without operation restarting after reboot
I (perhaps stupidly) decided to try to choose all images in Photos and drag and drop to a folder. I selected all in Photos, right click copy (took a while) then right click paste in finder. It didn't move any, just got beachball. It won't recover. I have tried reboots many times, it instantly opens with message:
The last time you opened Finder, it was force quit while reopening windows. Do you want to reopen its windows again. I have a beachball so can't click on 'dont reopen' and it actually looks greyed out anyway.
I have tried everything I can think of. rebooted and reset SMC, PRAM and NVRAM. No luck.
Used Activity Monitor to force kill processes (Finder not responding), no luck.
Clicked the 'i' in Activity Monitor which revealed Finder was being run by launchd, and that 'i' said it was being run by kernel task. I tried killing any i could, but they just pop back open and run again.
After each reboot i see Finder (in A.M.) is using 500% CPU.
I just can't kill it, it's as if there is a command stored somewhere and it's surviving reboots. I even tried getting PID from A.M. and using sudo kill PID, but same happens, just quits and starts again under a different PID.
grateful for any ideas! At this point the machine seems bricked. and no folders will display as Finder is hammering the CPU and unresponsive.
thanks
iMac 27″, macOS 10.13