windows 10. File explorer suddenly terribly slow

Took me days to figure this out - but here is how I went about identifying the root cause.

1. I confirmed that my issue was triggered a few seconds after login into my windows machine. I simply navigated directories upon login and 10-15 seconds later I would experience the issue.
2. To be certain it was a program and not the Windows OS I used msconfig and did a Selective startup with just Load system services. Restarted the computer, logged in and after 5 minutes or so I still had not experiencing the issue.
3. To narrow down the program I used Windows 10 Startup Apps - Disabled all then enabled one by one I enabled (restart on each change) until the found the culprit - Box Drive. Box Drive may not be the root cause for you but with this process you should be able to narrow down the issue, if its 3rd party software.
4. Other symptoms aside from a sluggish/unresponsive File Explorer were Unable to Shut Down or Restart properly (had to hold the power button to turn PC off)