Ugh. I did the update and had noticed something about Big Sir and Time Machine. I failed to copy and paste the info, but it was related to no longer using or backing up a Time Machine volume. If the volume is indicated as a Time Machine volume, running Big Sir, it will no longer be recognized/backed up (via CCC).
NOTE: I found the update notes!
Time Machine backup volumes are now explicitly disallowed as source or destination selections on Big Sur. We’re not planning to offer support for cloning to or from volumes that are flagged as Time Machine volumes.
Is this a concern for you? Not me, as I would never use TM volume for anything but that. However, what if I wanted to clone my TM and store (physically) offline? Maybe I am upgrading/replacing the HDD with larger (I have a 4TB in my Time Capsule/router as Apple discountinued product and support). I can clone the drive to another, I hope. But would need older version of Mac OS (non-Bug Sure…hehe I meant to type Big Slur, er Big Sir) and CCC. So beware of updating CCC if you aren’t running Big Sir. I may reach out to Bombich, but I don’t think its a bad thing…I mean, one shouldn’t clone to a TM volume…but what if you needed to clone TM to a NAS? Does anyone use TM volumes other than just backing up their mac?