Accused of cheating due to the time accounted by Blackboard
Unfortunately you can't prove a negative. You have been &quot;caught&quot; by a system that is insufficiently accurate to properly evaluate your actions (and those of many others).
All you can really do is insist (and keep insisting) to your professor that you didn't cheat and explain how you actually acted. If you don't get satisfaction then escalate the issue to higher authorities.
And keep insisting. People have an obligation to be fair.
A recent article in the Washington Post explores how badly online testing systems are performing. While the article focuses on fully automated systems, the problem is much wider, even when human &quot;proctors&quot; are used in conjunction with webcams. In my view the real problem is in trying to apply solutions from a different era into the current pandemic/online situation. Those solutions no longer work and the workarounds are badly failing. They make assumptions that are not valid given the range of normal human actions.
Any cheating detection system, automated or not, needs to have the property that it produces zero false positives. The meeting is part of that system and should assure that you aren't accused wrongfully. But it isn't well understood that a system permitting no false positives will almost invariably produce some false negatives. But the consequences of error in a cheating detection system are so asymmetrical that such a rule is required.

Artificial Intelligence is certainly artificial but it is definitely not intelligent.

Note that I hesitated to edit this after so many votes had been cast, not wanting to invalidate decisions made already by users. The advice remains the same. Insist that you didn't cheat and stick with it.