1. While it may not be advisable to do so, is there a way of stopping a preclear prematurely, other then rebooting your system or physically disconnecting the drive?

2. Is there anywhere that stores a history of preclears? If I wanted to check whether or not I had precleared a drive, could I check in a history or log?

Clicking on the red X that indicates 'clear stats' stopped the preclear.

1. While it may not be advisable to do so, is there a way of stopping a preclear prematurely, other then rebooting your system or physically disconnecting the drive?

2. Is there anywhere that stores a history of preclears? If I wanted to check whether or not I had precleared a drive, could I check in a history or log?

 

I don't know that a full history is stored anywhere, but the before and after smart reports should be stored on the flash drive. I don't recall the exact folder but there should be one with the before / after smart reports at least.